Lodsys, the patent holding company that has been accusing iOS developers of infringing its in-app purchasing IP, today finds itself on the receiving end of a legal complaint: a request for declaratory judgment brought against it by a company whose customers it's been threatening.

And interestingly, these customers aren't app developers, they're large companies like Best Buy and Adidas.

Filed in Chicago federal district court by online customer satisfaction survey outfit ForeSee Results, the document accuses Lodsys of sending infringement claim letters to certain of its clients in an attempt to muscle them into licensing deals. From the suit:

On or about April 19, 2011, Defendant sent a letter to Adidas AG ("Adidas"). In the letter, Defendant states "[w]e have reviewed your use of the Lodsys Patents and have prepared the enclosed claim chart demonstrating at least one instance of how you utilize the inventions embodied in the Lodsys Patents. The images used in the charts are representative only and in addition to the charted claim of the referenced patent, you should consider the remaining claims of that patent and the other Lodsys Patents both respect [sic] to the charted utilization and with respect to other products and services offered by you." The April 19, 2011 letter also included an offer of license under the '908 patent, the '834 patent, the '078 patent and/or the '565 patent.

Sounds about like what some small iOS developers have been going through lately, doesn't it?

Anyway, ForeSee denies the alleged infringement, and it's seeking a declaration that Lodsys' patent claims are invalid along with a permanent restraining order forcing Lodsys to stop disrupting its business and harassing its customers.

A few things to bear in mind here: As I noted earlier, ForeSee's clients aren't small app developers. That said, small app developers stand to benefit from this filing because ForeSee is requesting declaratory judgment against a group of four Lodsys patents that includes the two it has sued them for infringing. If it's granted, it will lend quite a bit of credence to their own invalidity arguments. As IP activist Florian Mueller notes, "If ForeSee's declaratory judgment action against Lodsys succeeded before the case against the seven little app developers is decided, it could be helpful."