Where have all the big guys gone?

[Halfdeck]

Also... Are the adult sites judged by a different algorithm than mainstream?

I doubt it, but it's far easier for me to get a mainstream site fully indexed in both Google and Yahoo.

In general, the percentage of exchanged links to the total number of IBLs for a site in some mainstream spaces (specifically, sites that publish articles like Wikipedia) may be lower than in adult, simply because people naturally link to articles as points of reference.

In adult, I basically see five types of links: 1) aff links 2) internal nav links 3) link trades 4) traffic trades 5) links to our own sites. One-way "citations" aka "traffic leaks" are rare.