Facebook recently started taking applications for beta testers of their new questions products (TechCrunch coverage here). The application itself is interesting in that it is far more thorough than the standard name & email process. Facebook outlines the vision of the product and then asks for three sample questions and answers... and promises a response within 24 hours. They include guidelines and a sample question / answer: Also notable is that promotional 'ads' for applicants are now appearing in the right column of the Facebook homepage.
The ad encourages users to apply to become beta testers... and while the landing page is specifically geared towards the Q&A product, the ad creative doesn't mention it. Rather, the ad speaks of beta testing future "Facebook products". Considering the value of the ad's real estate (typically reserved for high impact activities: ads, birthdays, invites, requests, etc), you can expect that other products are in the works and beta testing plays a key role.