Actually, I like tags - if they are used as just that. However, they have a huge disadvantage compared with categories: tags are flat, categories are nested. Therefore, I can narrow down a category search in several steps, whereas with the new tag system, I have to read a good part of the tag cloud to find what I'm looking for. Even worse: The tags in the tag cloud are scattered arbitrarily, so reading and finding what I look for is harder than in a simple sorted list.
Please, keep the tags, but consider bringing back the good old category system. The site is much less usable than it used to be. :-(