While the world falls in love with folksonomies and tagging, Dare Obansanjo mutters "Bah humbug, seen it all before".
All the problems with META tags are still valid today most important being the fact that people lie especially spammers and that even well intentioned people tend to categorize things incorrectly or according to their prejudices.
Not sure whether I agree with him or not, but it's Monday morning, I've been ill for most of the week, and I'm feeling contrary.
I have to say that Technorati tags will largely result in junk... however, since they use MT's categories, they might get some tags to work correctly, such as a tag titled 'Apple' or 'Music' will likely be mostly used appropriately. However, will this lead to the fabled 'semantic web'?? I have to say no way.
I love tags, but see them being beneficial primarily for personal use right now. del.icio.us is a great example of tags put to good use, however they work best when one person makes all the tags. Most of my tags are setup for my personal organization (like 'summer-job') but some tags ('cooking', 'photography') have a broader use and are useful on a global level.