Likes & interests in FB ad creation

When setting up a FB ad, you can obviously target your audience based on their likes and interests. This way it’s possible for instance to address everybody who is fan of the Techcrunch page. What I’ve noticed, though, is that not every fan page is listed there. Does anyone know if there’s a certain threshold like the number of fans a page needs to have in order to appear there?

Yes, there are thresholds in posts, users and activity. Obviously if you are the page admin the rules are different and you can truly target your own fans at any size page.