As is now commonly reported a huge number of large and reputable websites have been hit by a serious PageRank reduction. Here are some notable penalties for trusted sources of good content

http://www.autoblog.com/ PR6 PR4
http://www.engadget.com/   PR7 PR5
http://www.problogger.net/ PR6 PR4
http://www.copyblogger.com/ PR6 PR4
http://www.joystiq.com/ PR6 PR4
http://www.tuaw.com/ PR6 PR4

A few search and money related sites as examples

http://www.searchengineguide.com PR7 PR4
http://www.searchenginejournal.com PR7 PR4
http://www.johnchow.com PR6 PR4
http://www.quickonlinetips.com/  PR6 PR3
http://weblogtoolscollection.com/ PR6 PR4
http://andybeard.eu PR5 PR3
Vlad PR4 PR2

The speculation, which supposedly has almost been confirmed by a Danny Sullivan inside source, is that the penalties to page ranks have been put down to all this non-sense with paid links.

Google's guidelines ask you:

"Don't participate in link schemes designed to increase your site's ranking or PageRank. In particular, avoid links to web spammers or "bad neighborhoods" on the web, as your own ranking may be affected adversely by those links."

However many of the websites hit have been reputable sites that are not participating in any of the scheme quoted above. They are however part of massive blog networks that are all interlinking with each other, which Google has 'seemingly' slapped them for.  At the end of the day isn't inter-linking with your friends sites or closely knitted groups of sites FREE and not payed?

On a lighter note.... ....check back soon for some exclusive information on the UK Search Engine Marketing Benchmark Report. Search Engine War has been given permission to release summary's of some of the definative SEM report of 2007!