Content quality...
Satans_Apprentice
SERLists.com
I don't know how many of you are aware of it, but the Big G has been handing out an unprecedented number of manual penalties over the last 60 days. A rumor running around is that there is a new algorithm that flags bad/suspicious content for manual review.
The hummingbird algorithm is also pretty good at identifying shitty content. Even if it's not pointed at your money site, I believe that Hummingbird may be severely hurting the indexing rate for crappy spun content. To counter this:
1. Only use high quality spun content for tier 1 links pointing to your money site. This will probably reduce the probability of a manual penalty. If a Google reviewer takes a really hard look, you may get whacked anyway, but better safe than sorry.
2. If you are in a popular niche, you might want to use a service like Article Builder for Tiers 2 and 3. You may get more links indexed. Another alternative is WordAI for auto spinning.
3. I general, if you want long-lasting links and results, quality spun content is probably the way to go. Google's anti-spam algorithms are getting better every day, and the big G has been investing ridiculous amounts of money in Semantic Search. They've been buying up companies and patents like crazy.
The team at SERLists hasn't tested our theory yet re: quality content and indexing rate., but it is going to be on the drawing board.