1) Any of the sites that comply with the T&Cs may be added to the account, I just checked with tech support on this earlier in the day. You can read what makes a site acceptable within the 'Program Policy.'
2) I don't remember, but ad inventory is on the low side so running multiple units for my niche would not make too much sense and I imagine that the case is similar for other topics.
3) I'd rather they keep up the high paying clicks.
1- I think red in T&C that you can place ads only on the site is approved for beta program.
==> " 11- Abuse of Services. You agree not to: j- display all or part of the Ad Unit on any web site that is not enrolled in the Beta Program, or sublicense or syndicate the Matched Ads to any other entity or web site"
shez, according to the email from tech support any site that is owned by the accepted publisher that meets the publishing standards is able to display the ad code.
If in question mail tech support and if the answer differs then please post it here.
The targetted ads come and go for me. I got my first batch of targetted ads in about 12 hours, but from then on they become more and less targetted as the day goes on. I have ypn on 5 sites right now and the music one is perfect but the travel one ranges from location specific ads to mortgage, credit card and bankruptcy.