Following-up on its cease-and-desist letter sent last month, Craigslist has now filed a lawsuit alleging copyright infringement against PadMapper, a website that plots Craigslist apartment listings on a map and makes it much easier to use.

Craigslist also sent similar cease-and-desist letters to Carsabi (which Ars profiled in April 2012) and Mapskrieg, which use the site’s data to show used car listings and apartment listings, respectively. The three sites received similar letters from Craigslist’s counsel in June, alleging violations of Craigslist’s Terms of Service.

In the lawsuit (PDF) filed in a San Francisco federal court, Craigslist charges PadMapper with copyright infringement, breach of contract, trademark infringement, and unfair competition, among others. The lawsuit also names 3Taps, a San Francisco startup which openly scrapes Craigslist data and makes it available to other websites, and Does 1-25 as defendants.

The move seems rather odd for the for-profit company that has been a darling of the Bay Area Internet community for more than a decade. Most of us have used Craigslist to find all kinds of things, ranging from jobs to apartments and cars. (Heck, I found my cat on Craigslist’s free section seven years ago!) But if there’s one thing that has frustrated Internet users for years now, it's Craigslist’s lack of a proper interface, which these sites have attempted to bring to the fore.

Neither Craigslist CEO Jim Buckmaster, nor its counsel or spokesperson have responded to repeated requests for comment. 3Taps has also not responded to multiple media inquiries.

"I can say that our culture has always been community-driven, and what they tell us, in large numbers and for years, [is] that their posts are not to be used by others for profit," Craig Newmark, the company's founder, wrote Ars in an e-mail last month, adding that as a customer service representative, and not the CEO, he could not speak for the company.

In an e-mail to Ars sent just after this article originally posted, Eric DeMenthon, PadMapper’s founder wrote that he only found out about the suit on Tuesday, and is currently looking for counsel now.

"3Taps doesn't get any data from Craigslist directly, they get it from the Google cache, which is the difference—before I was just crawling, à la Google," he wrote. "Since I'm not actually re-posting the content of the listings, just the facts about the listings, I figured (with legal advice) that there was no real copyright issue there."

PadMapper restored Craigslist listings in early July

Craigslist does provide a license to companies that want to use the Craigslist data for mobile devices. In the court filing, Craigslist says that “PadMapper was offered a license to such content, but did not accept the terms.”

In a blog post from earlier this month, Eric DeMenthon, PadMapper’s founder, wrote on a company blog that by using 3Taps’ data, that he would be able to re-include Craigslist data on his site, after having removed it in June.

“I’ve found a way to include them that I’m told is legally kosher since it doesn’t touch their servers at all, but it still seems somewhat dickish to go against their wishes in this, and I’ve always had a lot of respect for what they’ve done for the world,” he wrote. “Also, court seems like it’d be no fun.”

DeMenthon wrote to Ars to say that the license Craigslist was offering was a mobile-only app, and given that PadMapper is Web-only, it was a non-starter.

Craigslist forbids scraping

Craigslist makes all of its money from broker-listed apartments and job listings in a handful of cities around the world. Other ads don't generate revenue, a situation which has left some Craigslist fans scratching their heads.

“I don’t get how this hurts their bottom line,” said Lila Bailey, a fellow at the UC Berkeley School of Law, in a phone interview with Ars last month.

The question is, then, if Craigslist isn’t losing money, why would it be so strongly enforcing copyright on its listings that other companies want to make more usable? Bailey added that Craigslist’s own Terms of Service forbid scraping.

As the Terms themselves state: “Any copying, aggregation, display, distribution, performance or derivative use of Craigslist or any content posted on Craigslist whether done directly or through intermediaries (including but not limited to by means of spiders, robots, crawlers, scrapers, framing, iframes or RSS feeds) is prohibited.”

“What it says is that as a user, you give Craigslist basically a non-exclusive license to show data around the world, and you assign them the right to enforce other people for scraping,” Bailey added. “As a user, you’re not giving up rights to your data, but you’re giving them this proxy to see whether other people are ‘stealing’ it.”

DeMenthon added that he would be open to working with Craigslist, but that the company does not seem to want to.

"If Craigslist is willing to talk, I'd be willing to consider changing what they find objectionable about the site, if it's something other than showing search results from Craigslist," he added.

"If they're worried about PadLister as a competitor, I'd be willing to consider turning that off if I could work with Craigslist instead. I've always viewed that as a backup plan, and while PadMapper had Craigslist, I didn't have any strong reason to push that very hard, so I didn't. I obviously have a lot of thinking to do, but I'd love to actually be able to talk to them and see what would make them happy with PadMapper continuing to operate and serve users. PadMapper does make some money (the servers would bankrupt me otherwise), but much less than if my goal was just to make a lot of money. As far as amount, I'm the only person working full-time on the site, I pay myself below market rate, and [PadMapper] as a whole has just about broken even overall. This isn't due to lack of usage."