Understanding Flash
 

I am in the process of learning Flash for Video delivery. Watching Lynda.com tutorials ect, but can someone point me to some info thats a very basic explanation of Flash,Flash players ?
What i mean is I can output in Quicktime Windows Mdeia player and Flash.
I can play back the Quicktime and Windows files with their players. I cant playback flash videos and I know it has to do with the player, the correct version ect
I have an older player that I got from a forum member as a free download but what Im asking is why cant I output from Adobe or FCP to a flash video then send it to a site like Vimeo( I know vimeo cant accept Flash, I was wondering if there is anywhere I can send my video and watch it in Flash)

And sorry if this is a long winded question

I just dont get Flash

KMPlayer will play your Flash files together with almost any other video file.

So will VLC media player. Free too!