Most of these websites fall into the category of filiopietistic efforts by well-meaning native speakers of Tamil who currently live outside India or Sri Lanka, and have an interest in being able to use electronic fonts for Tamil in one way or another. Most of the site owners are professionals in the hard sciences, who wish somehow to help maintain the Tamil language for their children who are growing up without a knowledge of the literary language, and their idea of how to do this is to put Tamil classical literature on the Web. Perhaps the underlying idea is that seeing Tamil on the Web will make their children view Tamil as a viable modern language; unfortunately the choice of classical texts belies this intention. The result is a great deal of unusable material, often wrongly modernized in orthography (children born since 1978 cannot easily read pre-1978 orthography) but of no use to elementary language-learners, including the very children of Tamils living abroad.
In my opinion the only useful `Tamil' websites are a few that provide fonts, either for Macintosh or for DOS/Unix systems, with no commentary or editing by the provider. One of these is the Singapore website managed by Mr. Naa Govindasamy (http://irdu.nus.sg/tamilweb), and another is Dr. Kalyanasundaram's site (http://dcwww.epfl.ch.icp/ICP-2/tamil.html) at the Swiss Federal Institute of Technology in Lausanne . The Singapore site offers an easily downloable package of fonts (in zipped format, with the unzip package included) that allow screen display for any user. This seems the easiest way to handle screen display (and downloading printing) and I have in fact installed these fonts on my own webpage for this purpose. What will be necessary will be the construction of various conversion routines so that the underlying source code (either in roman transcription or in upper-ascii format) for the many different Tamil font systems in which extant materials already exist can be converted to the Singapore system, and then passed on to users of our site.