I've clicked on those ads that they have now already. And since they were interesting things, I'm likely to keep an eye on that area for the foreseeable future, to see if anything else neat crops up.

Seems like an excellent way to roll-out ads... first, make the users look at the area where you'll place the ads, by putting interesting stuff there, and then put paid ads there.

So long as most ads remain relatively interesting/targeted, I'll keep looking. And probably clicking, too.

Consider also that Twitter users are very used to clicking on external links, because we do it all the time for links tweeted by others. I am much less likely to click on an external link in FB than on Twitter.