These are similar to the videos in that they are great at presenting chess ideas. There are also often lectures from Masters and International Masters which again I think have been very fascinating to watch. The Internet has a ton of interesting information out there. I enjoy reading the Rec. I am not sure that reading these groups will improve your game much, but again I think that they provide interesting information, and provide ideas at times.
Books are probably the most common way of studying chess.
I am not a huge collector of chess books, although I have read a fair number. When I first started playing many of the chess books out there were too advanced for me, but now I am at a point where I can better absorb a lot of the information in these books than I was before. The newsgroups I mentioned love to get into the arguments about which chess books are the best. I enjoy books by Seriwan, and find them very useful. One final method that I will mention is getting a chess teacher.