I'm a little sceptical.
It's a good idea on paper, but what do you expect to learn if you're speaking with people of your level or not-so-better than you? There are no fluent people in your list as far as I'm aware, and I'm afraid one would get used to do errors because of this.
Even on TSR sometimes people reply in a thread and all seem to agree on the translation or grammar one has posted, despite it being sometimes *very* wrong.
So I guess you'd need fluent people to talk to you? But then it takes time to correct someone decently. I remember spending sometimes one hour or more to check some text that was submitted here, because I had to make sure I was correct, I had to understand the grammar behind it (because I speak correctly by habit but there are loads of rules I forgot), and then I had to explain it in a clear, concise and educational way.
While the learner is happy to spend this time on learning, I know that I'd much rather revise my Japanese for my test tomorrow than "waste" time teaching. Writing is fine, I write when I can and I'm not asked to always check everything that people ask on this subforum (thank god) but speaking suggests similar availability (hai timezones, good thing we're almost all GMT or GMT+1) of both the learner and the teacher.
Then again, I've been told I was being overly negative during the last two days. What I think is severly lacking anyway is: fluent people/natives, availability of the members. The ideal case would be that couples emerge: ie if one is to be taught French by a French person, they should return the favour by teaching English or whatever language they're fluent in. So we have a real interaction and both get something out of it.