Paid links - where's the risk again?

I woke up this morning thinking about how I'm going to promote a couple of my secondary sites. And I got to thinking about all the effort I put into hand building white hat, quality links. Sure it works.

But so do paid links. And I'm seriously starting to question how big the risk is. More to the point, I'm starting to think that the risk is minimal.

- paid links have been around for years.
- they're easy to get
- they work. people rank just on bought links, and on very competitive terms.
- except in a very few cases, Google isn't doing anything obvious to stop them. (which would be the risk).
- Google hasn't been doing anything obvious to stop them in years.
- The serps are filthy with people ranking over the long term using paid links.
- the serps are still fine. Nobody's complaining Google's serps are full of spam or junk. In fact, there's probably less complaints than there were before paid links became commonplace.

In short, the risk is having your site penalized or booted out. But that's not happening -and hasn't happened in the long term. I was concerned about risk over the first year or two, but year after year after year people continue to rank without problem using paid links.

So remind me again, what's the risk? Why am I not doing paid links as a primary strategy?