I have a few questions about 'Placement ' Targeted Ads, I would apprecite any help:

1-Why do our sites gets targeted some time, and not all the time? in other words, why do advertisers decide to target my site for example? Most of my ads are Contexual of course, but lately I have been seeing a lot of Targeted ads. (I am assuming this is a good thing)

2-Do 'Targeted ads' pay per click only or do they also pay per view?

3-Can we find our who these avdertisers that are 'Targeting' our site/sections, are?

4-How can I get more advertisers to target my site? I know by default, advertisers should be able to find me. But what else can I do to make them target my site more? does the new AdManager help with this?

5- Everytime I get 'Placement' targeted Ads. , my earnings are usually much higher. Is that the case always?

It is amazing, I have been with Adsense for 3.5 years exactly, but didn't know much about Contexual vs. Placement targeted ads. And now I want to learn about them as much as I can.

Thanks in advance