Seb7 - 5:49 am on Apr 27, 2012 (gmt 0)
Most of the sites being hit were using anchor text links from low quality sites
One of my site's by its very nature attracts lots of backlinks from low quality sites, but doesnt seem to have been hit. Still in top place for its main keywords. Though there was around 4% drop in traffic between the 15 March to 2 April.
Wow, Ive just noticed one of my others sites, which has very few but solid authoritative links has taken a massive hit this week.