Nik, I think you may have just re-opened a can of worms!
The green blobs as they are known are the level of Credibility that that person is supposed to have. You can award some credibility points to someone if you think they have been helpful (to me for example
!) or you can take them away. You do this by clicking on the little box that has a tick in it in the persons profile on the left hand side.
A lot of people don't like the blobs, a lot of people have a good few blobs but don't really know what they are talking about (like me) and some people seem not to have any blobs but are very brainy about all things RIBs.
Pretty much everyone on here is very helpful in their own kind of way (as shown in your "new rib" thread) and you'll get to know who is who pretty soon!
PS so are you one of my lecturers at soton uni?! perhaps you are the person who gave me this bugger of a project to do!