The only thing that the group has in common is that they are all my Livemocha friends.
Probably none of them thinks of themselves as linguists -- just people who want to learn languages.
One, for example, whose username is Branka, a Croatian and English native speaker, is spending an unbelievable amount of time studying languages on that site.
Today, I began to study a language again, because I remembered how interesting it is -- along with the community you find. I chose Swedish for now.
The language lessons are set up as "parallel texts" so that if you go from one language to another, the material is the same. I should probably start to diagram the material.