Beware, The Nasty Secret Of The Craigslist Free Section

By Paul Michael on 13 April 2009 23 comments
Photo: InfoMofo

If you love Craigslist, and use the free section to either post products or get great deals, you really need to read this. Because there’s a dirty secret to Craigslist that most people don’t know about it, and the free section gets hit with it most.

As with all services or products used en masse, adaptations arise to evolve the idea. With eBay, it was bid sniping (which is legitimate in my book). With free software trials, product key generators hit the market, turning free trial software into the full-blown product. And now, with Craigslist, there’s something called Auto Flagging Software, and it gives the people who use it a very sly advantage.

Now, it turns out that Auto Flagging Software originally had a good use. The idea was to use it to blast SPAM and ads for sexual services, clearing out the trash from Craigslist and keeping customers safe from bad deals and illicit offers.

But other people saw a use for this software, and it is being used by two distinct sets of Craigslist users.

First, anyone who has competitors on Craigslist (this can be people offering similar services or selling similar products) are using Auto Flagging Software programs to flag the competition, thus giving themselves more of a chance of getting business.

Second are the users who want a particular product and don’t want anyone else to have it. This most often manifests in the free section, where great deals are be had and kind people will often just give away something with inherent value to a needy person.

When the sly Craigslister with Auto Flagging Software spies a real bargain, they pounce. The software does two jobs; it will send an email to the Craigslist poster requesting the item; then, it sends flagging signals to Craigslist about that post using multiple IP addresses. This will automatically trigger the ad to be pulled from the site. And voila, the underhanded Craigslister has eliminated anyone else from responding by pulling the ad, giving him or her the best chance of getting your deal. These pieces of software are most often used by people looking to make a profit be reselling cheap or free items.

I did a little digging round and found several instances of the software (I won’t be posting any links here, for obvious reasons). I also found people requesting custom-built versions of the software for their own nefarious purposes.

So if you do frequent Craigslist, especially as someone who regularly gives products away  in the free section, please monitor your post and don’t just give the product away to the first person who responds. It could be that Auto Flagging Software was involved and someone who genuinely needed the product was shut out be someone else just looking to make a quick profit from your generosity.

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23 discussions

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Guest's picture

Isn't it frustrating when people do underhanded things like this! I wish that Craigslist made some change such as only removing items flagged 3 or more times.


Guest's picture

Craigslist is a cesspool these days. Just try posting ANYTHING in the pets section. The flaggers are rampant.

Freecyle is awesome! You can post both wanted items and offered items. The postings are moderated and you don't have to worry about your ad being flagged by someone who is unscrupulous.

When I give away an item or items, I usually wait 12-18 hours so that everyone has a chance to request the item and then I'm free to give it away to who I want.

Guest's picture

Interesting info. I'll keep it in mind if I ever venture into the CL Free section again. I used to list things for free all the time, but I got tired of dealing with the nutty people who would respond. TJ's "cesspool" description is pretty accurate. I've been using Freecycle and find that it is a whole different world. People are polite, they actually show up, most of them say "thanks" for an item.

Guest's picture

re TJ

Most pets are not allowed to be sold/traded/etc. via Craigslist. See

"Partial list of items for sale and services the advertisement of which is not permitted on craigslist:
# Household pets of any kind including but not limited to dogs, cats, primates, cage birds, rodents, reptiles, amphibians, fish. Re-homing with small adoption fee OK
# Pet animal parts, blood, or fluids - including but not limited to stud/breeding service "

Guest's picture
Peter T

Maybe Craigslist could respond more flexible to flagging, like shifting the flagged post to a second tier, called "flagged section". There people could give positive flaggings, too, moving the posting to a higher ranking in the second tier, which makes is easier for customers to look for it.

Guest's picture

Auto-Flagging software could be detected by CL servers. However, this would cost CL more money to have dedicated servers that can do reverse IP lookups that verify an IP. The auto-flagging software cannot produce a valid 'verifiable' IP origin. The ball is in CL court on this. But I would guess that CL is not motivated to do anything since auto-flagging software keeps the posting volume on CL servers down. Obviously, according to standard system messages on CL, 'keeping craigslist uncluttered' is priority. With CL being in the top ten of the most traffic'd site in the world, the cost of keeping all that data online is a significant issue.

Guest's picture

I haven't had any problems with craigslist. I often sell AND give items away for free and have never had a listing flagged. I sometimes give away things an item at a time, but more often I just run a listing saying that things will be placed at the curb, first come, first take.

While auto-flag software does seem a little underhanded, why would I care who gets an item I'm giving away for free? Whether they need it for personal use or want to resell it is no business of mine. All I care about is getting it out of my home or garage.

Some recommend freecycle, but I haven't had good experiences with it. Maybe our group is just too large, but any time I've tried to get something I never get a response of any kind, and when I've tried to give something, I've had dozens of responses. The worse is when I promise something to someone and they never show up. I don't have that problem with craigslist.

Guest's picture

Interesting that people are trying to scavenge off a system like Craigslist. Let's hope they are aware of the situation and doing something about it. Thanks for the heads-up.

Guest's picture

When I used Craigslist to give away something, all I want is for that item to be gone. I don't care who takes it, just please take it.

One experience: had a big, heavy weight exercise machine. Tried to sell it but no buyers. Put it in for free with a picture and the phone immediately started ringing. Must have had 30 calls within the first hour. Some wanted me to deliver (no dice); some wanted it to be perfect; everyone else said they would be by to pick it up. One person finally showed up. I told him he would be responsible to get it out of my back yard into his borrowed panel truck. I feigned a bad back. He huffed & puffed and nearly had a heart attack. I ended up taking it apart for him and helping him get it into the truck. (Didn't want him dying on my driveway!)

Anyway, it's gone and I'm happy!

Guest's picture

I heard a story on NPR a while back about people who were using flagging to eliminate the competition. In the story, the people doing the flagging were "ladies of the night"--ironic that they were using the feature as a business tool when it was created to help filter out just the types services they are trying to sell.

Guest's picture

Freecycle is a good alternative to the Craigslist free section.

Guest's picture

as someone kept flagging them as inappropriate within a few hours of posting. I went on the forums and asked for advice in wording it and even then it kept getting flagged.

I have the same problem with freecycle- resellers are sitting by the computers all day sniping everything of value before people with real needs who have jobs or other responsibilities can put their requests in. there's no way to verify who's asking... maybe an authentication system of some sort would help....

Guest's picture

There seems to be a sort of craigslist 'government' in the shadows. I don't recall the free section of craigslist being allocated for 'needy' persons. Is it possible that the persons that get stuff free from CL and resell it are 'needy' themselves? And who is anyone to say they are not? I have not seen any publication of anyone getting 'filthy rich' from reselling items obtained for 'free', and if a person did, more power to them! Just because a person scrapes from the bottom does not make them any less of a person. And, the people that are giving away items seem to be happy that 'anyone' is picking them up.

Too many complainers, critics, etc spoil the soup...

Guest's picture
Joy Smith

I've never had any problems with freecycle, so I really believe it may be a better solution. I've given away and recieved items there. I've never used craigslist for freebies, but then again I don't live near a bigger city.

Guest's picture

I have bought and sold a lot of things on Craigslist and never had a problem. Last year I was selling a PVR and it keep getting flagged for no apparent reason. Then I noticed someone else was selling the same thing. I was wondering how they did it. Now I know.

Guest's picture

I'm sure the majority of the people here are listing legitimate items on craigslist. But, as a heavy user of it, I have to say that many (if not most) people don't bother reading the terms of use. That leads to flagging and that makes people unhappy.

Many people have no clue that they're either selling/giving away something on cl's "prohibited" list. Worse are the people who post in "Items wanted" for stuff on the "prohibited" list and then get irate that their post got flagged off. It's Craig's house and Craig's rules. And seeking a product creates just as much of a market as selling it or giving it away.

While I'm at it, cl is NOT an auction site. No "best" or "reasonable" offers. You know what price you want for an item; don't make the rest of us have to work at guessing.

Guest's picture

so if your ad gets flagged, put your contact info in the body of the ad, and the people reading via RSS will still be able to read and respond

Guest's picture

What a great post! Thank you for alerting all of us to this problem. We are about to sell some stuff on craigslist and give other things away. We are very glad that you wrote this post. Again, thanks!

Guest's picture

It is amazing the creativity that people can muster for an advantage . . .

Guest's picture

I have enjoyed posting items for sale on Craigslist for sale for year but within the last year I probably get 3 to 1 emails from people trying to sell me something versus someone answering the ad. Either that or they are harvesting email addresses to re-sell. All you have to do is answer the ad and they have your Email. My first clue is emails that are sent to me from 1-4am as they are coming from other countries.
People will also email you telling you they want to buy the item and will have"their people" pick it up and pay you with a cashiers check.
It's getting to be a real hassle to post an ad there due to the thousand of scammers who are also using that site.

Guest's picture


Guest's picture

more info!! i mean common dude!!!!?!?

Guest's picture

Glad this article surfaced! Hello Craigslist. Change your flagging policy for the new year. This underhanded method is used religiously by real estate brokers. My company's posts are always flagged for no reason other than for spite! There should be some accountability for flagging such as providing user/member info, etc. People without a CL account shouldn't be allowed to flag. Overall CL is a good product and concept, but the trash of society will always worm their way to undermine anything good.