It appears there was a mass Google PageRank update last night, the second for 2012.
At least 275 sites that we own or monitor have moved up or down (mainly up), but some sites in the more competitive lead-gen, travel and banking niches have dropped. One in particular went from a PR5 to PR1 in one fell swoop.
I suspect they had bought a bunch of links from blog networks.
I’m pleased Google is making things happen faster these days. There’s lot of Google Dancing going on so far this year.
Here’s some blog posts about Google PageRank for your enjoyment: