Well, this is a "feature" added by MedHelp to help identify members who give very good answers. Only the people who started the thread are able to choose this. They can choose only one and there is no way to undo it. MH encourages you to choose, but many of us feel that this adds a competitiveness to the forum that we, at least, don't need. Much of the information that we give out is cummulative and often comes from several members' input. Many other threads are of the type that there could not be a "best" answer.
Anyway, don't worry about it. We don't. And welcome to the forum. I saw your new post and I hope to have energy enough to add a response to it. I do invite you to read and ask and play around on the forum for support, info and general giggles.
You might want to take a look at the Health Pages. These are articles writtem by our members on topics that come up often. A good place to start - and bookmark is -
http://www.medhelp.org/health_pages/Multiple-Sclerosis/MS-Information-and-Resources-Index/show/22?cid=36
I am Quix, one of the Co-Community Leaders and a physician in a former (pre-MS) life. I try - along with the many scientists and knowledgeable people here - to provide good, solid, evidence-based information. Personally, I think we easily have the best MS forum on the net. Bias is good, lol.
Quix