As i understand ANY bought and forced traffic is against google TOS. And by reading through this forum i also see some people got into trouble with google after they bought hits. So better think twice.
If you mean buying hits to your contextual ads from google on your webpage, then that kind of unscrupulous tactic SHOULD be banned and I'm glad someone like Google has the Gall to step up to this junk! Mark
I was reading through the FAQ at Google and I don't see anywhere it says that purchasing traffic will get you banned. Be aware of how your site is promoted. Pages showing Google ads may never be loaded in an unrequested pop-up. This means publishers need to be very careful when purchasing traffic or setting up ad campaigns with third parties. Before contracting with any ad network, you should ensure that they will never display your site in pop-ups or as a result of the actions of any software application. This was found here: https://www.google.com/adsense/support/bin/answer.py?answer=23921&topic=8426
I emailed Google about buying targeted re-directed expired domain traffic and they told me it was ok for Adsense. Ive bought 5,000 so I'll see how it goes I think its just Adsense on sites that appear as pop-unders and pop-ups they disallow.