In the first stage, a participant spends most of their time learning the ropes. With a good coach, most people can be onto the next stage within a month or so. There is always more to learn, but there is a point at which one has "the basics".
After a participant learns to use the tools and has the basic idea behind online social interaction, they experience a period of information overload. In stage two, he/she learns how to focus their attention.
In the third and final stage of the learning curve, the big picture comes together and a participant begins to understand how they can use their new found capabilities. It is at this stage where one sees "why" they want to participate. And, it's usually not the same as the reasons that motivated them to learn in the first place.