That you happen to rely on links for your rankings and that you can't distinguish between paid links and non-paid links does not make every paid link blackhat SEO. Blackhat implies malice. You'd have to distinguish between a paid link that is an ad versus a paid link that is there just to improve search engine rank.
Good luck with that.
I can see why google has a problem with this but let's face it: short of looking at the books and being present during meetings you'll never know whether a link is:
(a) paid
(b) not paid
(c) just an ad
(d) an attempt at increasing search engine rank
It's not the same as ads - the guidelines only refers to paid links which pass PageRank (ie. Without nofollow on them).
Doing something to achieve an SEO benefit that is in contravention of the guidelines of the search engine you are optimising for, because you assume you can't or won't be caught (for example because they can't look at your books and weren't present during the meeting where you sold the link) is the definition of black hat SEO.
It may well be the case that Google lacks the ability to enforce certain aspects of their guidelines at some points in time, but as we have seen in the past couple of years when they do figure it out it can be a business closing event for some.
Much better to just follow the guidelines don't you think?
That you happen to rely on links for your rankings and that you can't distinguish between paid links and non-paid links does not make every paid link blackhat SEO. Blackhat implies malice. You'd have to distinguish between a paid link that is an ad versus a paid link that is there just to improve search engine rank.
Good luck with that.
I can see why google has a problem with this but let's face it: short of looking at the books and being present during meetings you'll never know whether a link is:
(a) paid (b) not paid
(c) just an ad (d) an attempt at increasing search engine rank