I find TD to be a good way to pass the time and obtain opinions from others living, visiting, or just interested in Thailand. If it did not exist, what other forms of banter are there available to one living in the LOS? Not much, in my opinion.
Even though I do not always agree with what is said on this site, it gives most people a way to unwind and have conversations as if you were in the corner bar (pub for those from the UK). The only limitation is that you cannot stare the other person in the eye or see their body language while they spew nonsense or deep and well thought out comments.
Personally, I joined TD to learn more about the subject of constructing a house in Thailand. Even though I had construction experience in the States, building a home in Thailand is quite a bit different when all the regulations and government agencies are taken out of the equation. Since a lot relies on which contractor you hire, your house could be a palace like SteveFarang's or a real disaster like what has unfortunately been discussed on this site.
Once I started exchanging thoughts and ideas about house building with others, I branched out into other areas I have an interest in. Finally, I did join in on some of the most ridiculous topics I would never have thought of. There are some very intelligent individual on TD and of course, there are those that are not the sharpest tack in the shed. It is the entertainment and deep thought that I now seek on TD and can not seem to find it anywhere else, at the moment.
Yes, TeakDoor is not perfect, but for now, I find it entertaining if not a little weird at times. What would we all be doing if there was not TeakDoor?