... would I need to learn? an interactive site, vaguely similar to neopets, but not really. something with real-time battles, but web-based, perhaps in a lightbox (where two or more players could battle in real time, with real results being relayed back), a chat system similar to gmail's chat for guilds, a shop system, a gaming system (probably flash.), a "who's currently on this map & what nation are they from/info about them when mouseover" system, etc. Just some ideas that've been churning in my head for a while. Basically, I want it to have the spirit of an SNES RPG, but with the elements of a fast-paced, competative web-based game. oh, and adorable graphics.
AJAX, which is mostly the same as JavaScript, but with the support of the XmlHTTPRequest, which makes the site REALLY interactive. Well, you would also need to know PHP or maybe ASP.NET to generate dynamic pages, and also a bit of SQL syntax. Believe me, start making a plain site in PHP and then practice a bit with AJAX, it's the best.
What Ricky said, and of course plain HTML, or you won't get too far. For the flash games I suppose you should learn the programming code used in Flash (I think that's a special language on it's own). Most important: HTML PHP MySQL JavaScript Ajax On another note: if you don't know any of these programming languages, I suggest you start with something easier than a whole online community...
Well, I know HTML. and I was prepared to learn PHP, but wow. I'd have to learn all those? I don't think I have the patience for all that. Maybe I should start smaller... What I was thinking of is releasing the web-game in stages, so as I learned, the game would expand. Think of this: Beta would start with some simple games to start earning in-game cash, and statistics for the players. The second stage would keep all the data from players, but start to include some new features. There would be two or three more tiers of this until the final release. I guess for what i'm wanting to make, i'd really need a team... I've got the whole concept developed, I just lack some of the means to produce it.