According to Wikipedia there are 65 million Tamil speakers in the world. The language is spoken in India, Sri Lanka, Malaysia, Singapore, and Mauritius.
If you are a native speaker there is probably still a goldmine of good prime generic .com terms available.
For the past few years I have been buying Hindi language IDN domains in .com said to be 400,000,000 plus native speakers of Hindi language.
But only a small percentage has access to the internet, though a small percentage of a ***load is still a *load of users. :P
Then there's also the issue of illiteracy, but I think it's safe to assume over 90% of those internet users can read.
While I don't know a lot about domaining, I think if you do go for these domains, Chinese, Hindi and Japanese (=Chinese) characters will be the safest bet.
Especially since eventhough there are various different language variations in China, most of them use the same characters (which have the same meaning but different pronounciation).
Plus, they're big economies. :P
Just my two cents.
Edit: Also, since I can see the characters with a freshly installed windows system I think it's safe to assume the tamil alphabet comes standard with windows (and probably Mac?), and since that sign is apparently popular among bloggers, if it's worth nothing as a website in Tamil, perhaps it's worth a little as a landing page for redirecting pages.
While looking for the correct way to type Tamil (as in the Tamil language (it's not Tamili or Tamilian, or anything else :P)), Wiki has a map with the distribution of people who speak Tamil around the world.
Seems it's mainly in North and South India, as well as all over the UK.
It won't let me post a link because I'm new, but you can find it in the Wiki article about Tamil language.
