Asking how 'blackhat' will be is a silly question on its own, as any whitehat method can be exploited in a way not commonly thought of. Hence, it will be completely dependent on its whitehat counterparts.
PPC will still be the most effective (and definitely efficient) method of advertising any product imaginable, and though guidelines change over time, decent marketers will be able to avoid search engine hostility and proceed as they always had.
The number of competitors will drop, as most marketers will either go on to better ventures or become part of a professional PPC company/consultation agency. Marketers like Mike Filsaime and <insert other random guru name> will hopefully go bankrupt or at least become inactive because people will understand info products can't possibly be sold for more than a physical copy (a book, that is -- not sure if you've heard of it). This is wishful thinking, admittedly, as it depends largely on the lessening of human stupidity.
CPA IS PPC (or other kinds of media buys). Article marketing, SEO, etc. have nothing on PPC, and for as long as CPA provides products, PPC will market them.
Facebook will probably still be viable, though I find the method needlessly tedious and wasteful (qua time). Twitter will have died as a viable marketing mechanism, and rightfully so.
That is how I imagine the future of IM. I also do palm reading, should anyone be interested.
~Iced