Co-founding
webwright: Hard to tell about the lion's share issue.  If the site has traction or good IP, it MIGHT be fair.  Probably not.  The question to ask is, "how hard would it be to duplicate the effort"?  The way to ask HIM is: "How much have you reduced my risk with your headstart?" and "If we take 4 years to build this and win, what percentage of the total effort/work/risk is your headstart?".If he's flailed for several years with limited success, that time is (unfortunately for him) not worth very much.If he wants blanket veto power over all decisions, I'd say bail if you aren't comfortable with it.The legal gray area is up to you-- YouTube certain was in gray territory.  Given the risk, asking for a formalized corporation to throw up a little liability screen isn't a bad idea.Regardless of all this DO NOT PROCEED without an agreement in place.  It doesn't have to be bulletproof.  It can be as simple as an memo of understanding, but there is too much up in the air right now and it'd be easy to be 6-months in and be wondering, "wait, how much equity do I get?".