Just a few weeks ago, Microsoft went in for a bit of sensationalism claiming that many open source software programs, including the Linux kernel itself, infringed on hundreds of patents they owned. There was a huge retaliation from this, with Linus himself demanding that Microsoft list said patents. They've come back, now, and their response is that they are just too busy to be bothered with listing them. Too busy? Indeed:

Microsoft patents attorney Jim Markwith told OSBC it would be "impossible" for Redmond's bureaucrats to respond to the volume of responses that would result form disclosure. Also, apparently, it's ungentlemanly to name names.
If they are too busy to list the patents and don't care enough to take the matter(s) to court, what was the point of bringing them up in the first place? No reason, of course, except to incite fear. Obviously, with their Novell partnership, they aren't just sitting on the issue. Their motives are anything but pure, though. You'd think that with a supposed 235 patents being infringed, they'd want to do at least something.