[necovek]

Launching a free (often restricted by number of users or "beta" for a limited time) version is a way to get users to experience your product and possibly get hooked.

It makes the most sense where you expect your actual hosting costs to be symbolic for small-scale users and hope to earn from bigger customers.

This practice has been present since the dawn of (software) time — even Microsoft never really bothered with private illegal copies of Windows (or DOS), knowing it will get future customers into the Windows world and they'll want Windows at work too.

However, going straight up with the paid model has been there forever as well: it mostly depends on your individual market evaluation and existing entrentchment.