You can not thank people until you are a Cavy Slave. To be a Cavy Slave you have to post 10 times and be a member for 30 days. When you are a Cavy Slave, a sign will appear on each post with the words "Thanks" in it and a small thumbs up picture. Click that and your username (in my case pigsforlife) will appear under the post.
For information on cavy status see this sticky
http://www.guineapigcages.com/forum/...es-titles.html .
I urge you to read all of the stickies located at the top of each forum, they hold invaluable information.