Google updates toolbar PageRank about four times a year. They updated it in August, and now they've updated it again. As you would expect, some sites are going up, and some are going down, but in both cases, webmasters are noticing.
As usual, people are taking to Twitter to voice their "excitement".
First good #news for today: our blog has just reached Google PageRank 4!
Quite happy. My new project jumped from PR:0 to PR:2 http://t.co/0svSa32s
Toolbar PageRank doesn't mean a lot, but people still like to monitor it. Here's the obligatory Matt Cutts video in which he talks about toolbar PageRank: