People buying domains for that price without complaining is also a BIG part of the problem. Paraguay has one of the most expensive TLD 44 USD, and probable the worst service. This is not an isolated case, is the reality in many other areas in my country, paraguayans running a public service abusing of other paraguayans. More and more people are buying domains outside ".py" because of that, overpriced and poor quality of service.

If you mean "tag" as the kind of a "post-it", like the tag for a picture or a file, then you are only talking about a little part of semantic web. Actually, semantic web is more complex than just tags joined to "build an ontology". It is based on several ontologies combined, and most of all, the use of a language that allows me to stablish semantic relations, which will allow me to do semantic queries like "what are other books this authos has written and are related to other investigations I'm doing now". If you want to give a try to a Semantic Desktop, the Nepomuk project http://nepomuk.semanticdesktop.org/xwiki/bin/view/Main1/ (IBM, HP, SAP, Mandriva among others, are participating) is building a very interesting solutions, PSWE is the desktop application (Eclipse RCP based) and have Nightly builds http://dev.nepomuk.semanticdesktop.org/download/, KDE is also working on having a semantic desktop, with colaboration from Nepomuk. One of the authors of Nepomuk, Leo Sauermann, did Gnowsis http://www.gnowsis.org/ from where some ideas were taken.