[jjordan]

Isn't that exactly what PageRank was designed to handle? None of these spammer sites should have any actual positive reputation.

[rhizome]

I wouldn't be surprised if there's a network of non-phone sites linking to them that juice their PR. Like I surmised: it's a broad-based strategy.

[trillic]

Google has cycle detection in PageRank specifically for this reason? They know which regions of the graph are good ones.