I am where I am due to people in my formulative years giving me advice and assisting me with different projects. I really appreciated it then and even now. I seem to learn much more when showed how and then do it in front of that person.
This site is a pay back for me. I don't get that many thank you's either, but I know now days people don't say that enough as we and they should. Like Bruce stated.
I know in my heart that the poster will read a valuable answer from one of us and take it to his/her project and walla, it came all together and they sat back and gleaned. If the thank you does come, great, if not, someone did use our advice and make a better project or decision.
When I do see a thank you, you better know that I remember that name and will go out of my way to help him/her on the next post. To me a thank you goes a long way and I will too.
I personally thank you for your keene observance and "being bugged" but do not worrry about it too long.