I have the secret as to how to utilise paid links without attracting a big Google Slap
The fact is, in competitive SERPs (proper ones, not the ones people SAY are competitive) paid links are a necessity. Overstock [webmasterworld.com], and JCP [webmasterworld.com] provide two examples that we can talk about here.
Many, many others abound. How do they avoid the Google Slap where mere mortals are relegated to the lower realms of the dungeon dimensions (also known as PAGE 5!)? Most established webmasters or SEOs know two things about paid links
1) (Almost) everyone does it
2) It can be a risk
It's a lot like bluffing in Poker. It's dangerous unless you know the hows, whys and whens of what you are doing. Its very hard to win without it. It hurts if you get caught. Any you're never quite sure exactly how much your opponents are doing.
So, when is it OK to buy links? Or rather, what factors shift the probability curve for getting the Google Slap (which is independant on whether taking that risk offers ROI- which could make for an interesting thread in itself). I have heard, sometimes from my own keypad, the nebulous concept of "brand" mooted as one posibility. Other, equally ill-defined, concepts include size [...OF WHAT?], link profile, or niche.
I'd love to hear what definitions and, if you're feeling particularly adventurous, values move sites toward immunity.
Ok, ok, I lied in about having the answer, but made you read, didn't I? Maybe if you contribute, we can come up with the answer together.