I think I read on here that MeeGo is also using tracker (correct me if I'm wrong)

thumbnailer/indexer and apt-worker/update checks are the reason for 95% of unresponsiveness problems I've had on my N900. I am using it for web browsing or whatever, things are going great and then suddenly it is nearly unusable for several minutes. Switch over to conky and sure enough one of those things is going full steam ahead.

The lag seemed to get much worse after PR1.2, I guess because much of it was moved to /opt which I believe is slower(?)