These graphs show the "opensolaris" search term popularity in Google. The spikes seem to correlate with the OpenSolaris releases: 2008.05, 2008.11, 2009.06. Over the last few months though, the searches seem to have gone down quite a bit. Perhaps further evidence EU's delayed decision is coming into play here.
OpenSolaris's next release (and the ZFS de-duplication awesomeness) should make it much more closer to LTS ready and boost it's popularity much further than ever before. Of course, we're just hoping. In our business, we are very much dependent on OpenSolaris's future.
Wouldn't worry too much about Google Insights results; they have a tendency to be irrationally biased.
@Saager, yup. We've seen stuff like this before, http://blog.entic.net/google-censorship-or-just-a-bad-search-engine.