sponsoredoverview.com is also ok

bidvertiser is good, u manually setect the ads you dont want to appear

I've read this thread with great interest, and it seems to be there's plenty of knowledgeable people in this forum.

I only have experience with AdSense, myself.

Does anybody know which of those different companies listed and discussed in the thread allows the use of PayPal?

I know for a fact that AdSense doesn't, but perhaps some other service...

There are many. But unfortunately nobody pays as good as Google adsense. I can see you guys haven't mentione another popular Contexual Network Clicksor. They also provide Contexual Advertising.

many pay by paypal... go through them and you will see

I believe valueclick.com is a good one but hard to get approved