Craigslist hates VoIP, Prepaid Cellular, Spammers….

Not sure how I missed this, I like to think of myself as being on top of the industry but I just came across this over the weekend.

Craigslist.org, the popular free classified ad site, has been at war with spammers for some time. According to some reports, 90+% of ads in some categories are generated by spambots. Craigslist has deployed countermeasures including CAPTCHA and other techniques, but spammers have quickly evolved their techniques to sidestep them.

A few months back, Craiglist instituted a telephone verification process that places an automated outbound call to a user placing a classified ad in certain categories. The call delivers a unique code using text to speech, which is then used by the poster to authenticate the ad they are placing.

This is an effective measure for dealing with spam, and a great thing for legitimizing the Craigslist user experience….but not so great if you are a Craigslist user and you also happen to be a VoIP or prepaid cellular user.

The problem is that Craigslist is categorically blocking legitimate VoIP and Pre-paid cellular users from authenticating themselves.

The phone verification process is fairly straight forward. When you place an ad in many categories on Craigslist, you are presented with the form below.

Craigslist blocks most VoIP phone numbers, including those from services like Grand Central and Tossable Digits. This is an apparent broad stroke to counter the use of such services by spammers to game Craigslist’s voice verification.

Craig’s uses a 3rd party service, ReduceFraud.com to screen out VoIP and Pre-paid cellular numbers, and will not deliver an automated verification call to a number that is determined to be such. (Since only SPAMMERS use VoIP and Pre-Paid Cellular!!!) What sophisticated algorithm does ReduceFraud.com use to identify VoIP numbers, you ask? They check the DID number to see who owns the NPA NXX X number block, and if the DID number is owned by Level 3 Communications, they classify it as VoIP of course. Whizbang!

Coincidentally, ReduceFraud.com is owned and operated by a CA firm called Telecentrex, who offers their own hosted VoIP service.

Amazingly, this has created a business opportunity for resourceful entrepreneurs. Literally dozens of services have popped up offering everything from VoIP DID Numbers that Craigslist classifies as Fixed Lines, to pre-authenticated Craigslist user accounts, to full-blown Craigslist Super Spammer Software Packages.

I even found programming requsts on e-Lance, Rentacoder and GetaFreeLanceer.com
offering to pay for workarounds.

I would love to find out which service provider Craigslist is using to delivery their automated outbound verification calls. It would be cost-prohibitive to incure circuit-switched LD charges to deliver all those millions of calls…..VoIPMonitor estimated nearly 24 million VoIP users by 2008 (i.e 24 Million frustrated, would-be Craigslist users)…..I would not be surprised to learn that the provider was leveraging VoIP to send these very same outbound verification calls. Now wouldn’t that be ironic?

Garrett Smith

Garrett is the former VoIP Supply CMO.

View Comments

  • And how about the irony that ReduceFraud.com has NO PHONE NUMBER AT ALL on their website and the number for Telecentrex (714) 408-4400 comes back as "Non-Fixed VoIP", iow a FRAUDSTER!

  • @David:

    We touched on that briefly on the Squawk box call yesterday. Honestly, it is tough to give them the benefit of the doubt on this.

  • It is really screwed up. I just sold to a legit advertiser a whole bunch of DIDs for one time use, it seems that my DIDs although they are VoIP are listed by them as "fixed line". go figure!

  • @Moshe

    I find it funny that a large organization (revenue and influence wise) would utilize a service that is so arbitrary.

  • I'm going to be a bit contrarian on this. Craigslist is in serious trouble about the spam and illegal posting stuff - they face lawsuits and even being shut down in some places because of the spammers. It is hard to argue that denying some percentage of users access to post ads is worse than denying all advertisers and potential buyers access.

    Which is of course not the same thing as not dealing with fixing their issues with voip-using potential advertisers. They clearly are going to need to do that - but maybe you should cast this as an opportunity for a smart voip entrepreneur to come up with a verification service that works and doesn't discriminate? The upside has to be good - craigslist is big business

  • Owen - I agree 100%....the title of my post was perhaps a bit provocative....but this is the ADD generation and it takes a little oomph to grab the attention of prospective readers these days.

    I see their efforts to date as band aids. I am not an expert in broad fundamental solutions like OpenID, I just saw their current methodology of voice verification to be inherently flawed.

    I sympathize wholeheartedly with the folks at Craigslist. Spam is a blight, but "throwing the baby out with the bathwater" is not a long term solution.

  • If they are doing something as detailed as checking the carrier, why not (instead of alienating 14 million subscribers), offer SMS validation, take a recorded voice sample, or offer the subscriber a faxable form? There are so many easy alternatives than a black-out approach. Cory Andrews "throwing the baby out" comment is dead on. Great article by the way.

  • Anyone notice that we just let San Fran have Legal Hookers??? Ummmm oh wait Craigslists crack team of 25 hippies are located in San Fran too.... and let me see they got the biggest US based online ad site with Escorts and Hookers all over the place Can you say Kick backs?

    Craigslist... shut down your Escort Pages You say you are non-profit you go on TV and the news saying you want to bring peace and love to the nation and world lets see it

    We all know what areas on craigslist are the "problems" LE and FBI know it, Craigslist knows it Take Escorts Off of Craigslist and you make the internet and world a better place. fricken hippies takin their corp kick backs in san fran makes me sick you guys are suppost to stand for something

  • Funny, I wanted to sign up for their service (reducefraud.com), but their demo wouldn't work and their contact form wouldn't work either because... I have Vonage!? So I called their domain registration contact number and left a message. Are there other services besides them?

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Garrett Smith

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