In addition, Matt said they will be “expiring” some of the penalties with this update. I assume the penalties refer to the toolbar PageRank massacre that began about ten months ago for selling paid links.
If you are new to Google PageRank, I suggest you read Danny’s What Is Google PageRank? A Guide For Searchers & Webmasters. Once you catch up with that, and you want to discuss the specifics of this particular toolbar PageRank update, I suggest you check out Mat Cutts and the Search Engine Roundtable, where I link over to the major forum discussion around the toobar PageRank update.