taberstruths - 11:20 am on Jun 29, 2013 (gmt 0)
If old or abandoned sites are rising to the top then the question is what do those types of sites have in common? Off the top of my head is that they either have a very small amount of links that have been built recently or that they are have not been changed recently. Both of those things could be unexpected consequences of an algo shift targeting link velocity or minor tweaks for SEO purposes.
Or it could be just the garbage rising to the top to be skimmed.