I’d noticed that Google Chrome (on my Mac, at least) was taking longer and longer to get started, and then I’d still have to wait for several minutes for any of my autocomplete history or favicons on the bookmarks bar to show up. As it turned out, I’d never cleared my history before, and that was really killing startup performance on what is otherwise a very, very fast browser. Of course, after clearing my history, all the URL auto-complete history I’d built up over months of use has to be restored, and that is mildly frustrating — but not necessarily as frustrating as waiting for the browser to get started.
If you’re looking to check the performance of your blog, check out Is My Blog Working?, a nifty site that examines your blog for functionality and performance troubles. I discovered it a year ago but I forgot the name of it until this evening, when I was testing a couple random optimizations I made to jaredwsmith.com (most notably WP-SuperCache). It gives you all sorts of interesting tidbits about your server and blog software which might help you find any issues with performance that might be keeping folks away.
Check out this list of memory-hungry Firefox extensions. The only one of these I use is ForecastFox, and that’ll be awful tough for me not to use. :) A good list though.