We've added a little 'Thanks' button on each post (down the bottom right next to the Reply and Quote buttons).
If there is a forum post entry that you find helpful simply click the 'Thanks' button to let the author know. It's great motivation for those who contribute. When you click Thanks a little message will appear under their post letting them know. This is only shown within the forums - it does
not appear out on other sites eg Facebook).
Other ways:
There is also a Facebook 'Like' button on each post. If you are on Facebook and want to share the post with your friends, simply click the 'Like' button and it will display on your Facebook profile.
We are experimenting with this feature at the moment, so feel free to make suggestions about whether you think it is a good idea or not.