And this time, because of a lawsuit from Thomson Reuters. Here's hoping this turns out for the best! Thanks to Mike Taylor for pointing out this news item (also here on Nature).
The basic gist of the lawsuit, apparently, is that the latest beta version of Zotero imports the Endnote style files, an alleged violation of the Endnote user agreement, among other things. Thomson Reuters alleges that the "reverse engineering" of their files (and allegedly, part of the software) is illegal. . .we'll see how this pans out, but I am not sure if I see the difference between what Zotero did and the file format translation capabilities of programs like Microsoft Office, etc.