Looking at alot of the posts on the forums here, it seem as though not alot of people understand who the precursors, forunners, or flood really are. There is even a whole advanced Human race that is around the forunner time but people are confused about that whole Backstory of Halo.
Thank god i found these videos on Youtube that explain really well what happened. If you dont know exactly who the Didact, or The Timeless One is check these videos out. Totally worth your time.
Let me help you
http://www.youtube.com/watch?v=SOUc0R0EVmA&feature=list_related&playnext=1&list=SPF358826562B99514
Cool, thanks for the post.