A new chapter is unfolding in the legal drama between classified ad service Craigslist, and third parties that repurpose its ads. Two months ago Craigslist asserted copyright claims against apartment hunting site PadMapper and its data provider 3Taps for using its user-submitted ads without permission, and now 3Taps is swinging back with a counterclaim accusing Craigslist of using anticompetitive tactics to maintain a monopoly on online classified ad markets.

The counterclaim, filed on September 24th, denies that Craigslist exclusively owns its users’ posts (which the company itself has recently conceded), and claims that by preventing others from searching its publicly available ads in more efficient ways, Craigslist is behaving like a monopolist. According to 3Taps, the company’s "‘strategy’ of ‘unbranding,’ ‘demonetizing,’ and ‘uncompeting’" has enabled it to generate revenues between $100 and $300 million a year "without sinking any significant costs into research and development or innovation."

The lawyers point to Craigslist's terrible search as evidence of stagnation

To drive the point home, 3Taps’s lawyers point to Craigslist’s "primitive user interface," which forces sellers to "‘guess’ at the regional Craigslist site most likely to result in a sale" and buyers to search regions and classifications separately. The experience is contrasted with more efficient "power searches" — say, those enabled by 3Taps’s API. It also notes that 3Taps performs these searches without consuming Craigslist’s bandwidth, by accessing Google’s cached versions of the company's pages.

In the final section of the impassioned document, 3Taps's lawyers say that Craigslist engages in "dirty tricks" to prevent competitors from accessing its content, including hiding ads submitted using competing services (such as PadMapper's own service, PadLister), and demanding Google to delete its cached versions of Craigslist ads, which 3Taps uses as the source for its data. "Through this multifacted scheme," the counterclaim reads, "Craigslist has sucked the oxygen out of the innovation demanded by consumers," and, "has caused 3Taps significant injury — in the form of millions of dollars of lost sunk cost investments and lost opportunities with its partners."