Second Life (SL) virtual world where you can meet people from different parts of the world, work, create and learn among other things. Actually, I use it as a place where I learn and share knowlege on Information and Communication Technology with collegues.
A cyber friend of mine has a blog on SL and she started a debate on what is the best way of making tutorials. The ones who are hearing impaired find it difficult to follow oral tutorials if there are not subtitles.
Here is the link to the debate if you are interested