So I will: Roughly summarized, Second Life missed its chance at mass market success by having heavy hardware requirements, a complicated user interface, and a confusing user experience that was not designed as a game even though the vast majority of its potential userbase wanted to play it as a game.

How many users does Second Life have?

In a recent interview with VICE News, Ebbe Altberg, the current CEO of Linden Lab, stated that Second Life has about 900,000 active users.

What exactly is Second Life?

Second Life is an online world in which residents create virtual representations of themselves, called avatars, and interact with other avatars, places or objects.