A premium, fee-based version of Socrative? (But don't worry)

Socrative is a great tool, and it's making plans right now to get better.

With Socrative you can write quiz questions, quick questions (T/F or short answer), and really cool review games for your students.  I use it a lot and my students love it (especially the Space Race game).

Now they're thinking of offering new services, such as expanding the maximum classroom size from 50 to 150 students, exporting results to gradebooks, and delivering multiple activities to multiple rooms simultaneously (that one sounds like it would be great for synchronous classroom vs. classroom competitions).

I just received an email from Socrative today asking if I would be willing to pay $29.99/year for these new planned premium services.  Not to worry: They reassure users that Socrative's existing core features will remain free.