Social language learning has become incredibly popular on the Web as it has transcended language barriers in previously impossible ways.
For example, right now someone in Argentina could be waiting to teach you Spanish in exchange for your English skills. Or maybe your native language is Spanish and you want to learn Mandarin Chinese in exchange for that knowledge - there's someone out there for that as well!
In fact, chances are there are hundreds or even thousands of potential language partners with whom you can symbiotically achieve your collective language learning goals.
These exchanges are manifested as instant messages, phone calls over the web (VoIP/Skype), organic groups created by members, etc.
Below is a growing list of resources specific to social language learning, online social language learning networks and other websites and Web services that are changing language learning worldwide.