ColourOfSpring - 2:05 pm on Mar 31, 2013 (gmt 0)
Like with state taxation, when over-taxing state ends up with *fewer* taxes collected, due to the contraction of the economy resulting from over-taxation, likewise with over-fighting spam you end up with more spam in return, because non-spam sites are burnt along with real-spam sites, rendering the risk of creating an expensive non-spam site unacceptable, therefore reverting to techniques of all sorts to remain viable.
heisje, GREAT comment - deserves a thread of its own (if a similar one hasn't already been started).
The cost and effort involved with starting up a new "proper" business online is much greater than starting up a new "non-proper" / spammier rank-and-bank site. Purely in terms of organic rankings, BOTH sites carry a high risk of being penalised by Google in some way. The "proper" non-spammy site is STILL high risk because it can easily have its content scraped by another site with more authorative links pointing to it, and be penalised for duplicate content, OR some outsider can spend $5 blasting it with crappy links and it gets penalised/penguined for unnatural links. For the spammier site, the cost and effort of starting again is a LOT lower and it can take greater risks, which mean better short-term rankings. Even if the non-spammy site never takes risks, it's STILL high risk - it won't have a decent link profile to protect it from spammy links, or for being seen as the canonical reference when it's scraped. This is why we're seeing more and more spam in the SERPs - genuine businesses just can't keep starting again.