TODO list for MoinMoin is on MoinMoinTodo. You are encouraged to add wishes and ideas to MoinMoinIdeas.
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"Moin" meaning "Good Morning", and "MoinMoin" being an emphasis, i.e. "A Very Good Morning". The name was obviously chosen for its WikiWikiNess.
No! Originally "MoinMoin" does not mean "Good Morning". "Moin" just means "good" or "nice" and in northern Germany it is used at any daytime, so "Good day" seems more appropriate. --MarkoSchulz
We use it all day in the south too. I always thought it just morphed from a morning greeting to an all-day one. -- JürgenHermann
Interesting. I always get puzzled looks from southerners when I use it in the evening. My wife - who speaks more Plattdeutsch than me - once explained to me, that MoinMoin originated in "Moi Dag" or "Moin Dag", which just means "Good day". I don't know whether the people were too lazy or just mumbled too much, anyway it degenerated into "Moin" or in its emphasized form "MoinMoin".
The whole thing gets more complicated since there are so many different flavors of Plattdeutsch. Someone from Hamburg might have a hard time understanding someone from the coast.-- MarkoSchulz
Sorry for barging in here, but I guess that is the idea with this anyhow 
I'm from the southern part of Denmark and we also use the term "Moin" - even though we spell it "Mojn"... but i guess that's because a lot of our language is influenced by Platt -- JørnHansen
Well, Platt is surely an extreme German dialect (or even its own language), so I guess it's no surprise.
Swedish has the greeting "morn morn", which is a sloppy way of saying "morgon morgon", which means "morning morning" and is thus used to greet people during the early hours. Coincidence? -- ChristianSunesson
How is moinmoin pronounced? [Although it's an open question as to how to represent the phonemes across Swedish, Danish, Platt Deutsch and Enlish...although probably not impossible as they are all 'Germanic' languages...] -- Nicholas Spies
It's pronounced the way you spell it... m as in my, oi as oy in doytshmark, n as in nuts :).
BTW, one could resolve to accepting *both* theories on The Origin Of MoinMoin---taking into account the nearness in both sound and meaning over several neighbouring languages (Platt, H.-German, Dutch, Swedish, English...). Platt used to be the lingua franca of the Hanse (an early, nautically and commercially oriented ancestor of today's Internet), and a lot of words must have been shared among the people engaged in the international trade across the North and Baltic Seas.--- G.: 'Morgen': early day, next day.--- E.: 'next morn' approx.= next day (cf. also E.: 'day' in 'day and night' vs. 'day' in 'every day').--- Perhaps moinmoin even comes from 'moin morn'?---In (N.) Germany, one often says 'Morgen, Tag, Abend' (in IPA spelling: [mo:en, tax, a:mt]) instead of the more polite and more carefully pronounced, official forms 'Guten Morgen' and so on.
--Wolfgang Lipp [lipp@epost.de]
In Scots, 'morn' can mean either morning or tomorrow. Thus the morn's morn is tomorrow morning. --Hamish Lawson