Everyone who buys Minecraft will get free patches, whenever they buy/bought it.
Those that bought it in Alpha got 50% off, those in beta get 25% off.
In addition, anyone who bought Alpha will get any future extensions for free too, (whereas Beta-buyers and onwards will have to pay for those extensions).
Oh, and as for different client/server versions - that'll no doubt be like most games - i.e. they need to match, (at a functional level - using different skins is probably fine).
(The next upgrade is going to give users the choice of whether to upgrade or not, so the potential for different clients is will immediately increase anyway.)
Ah they way I read it, anyone that bought it at Alpha got any little updates, whereas anyone that bought it at Beta won't get those little updates, just the completed game when it's finished, or possibly major updates as well in the meantime.
Anyone playing single player found any fun map seeds?
There are threads on various forums discussing this, but they seem to be mostly populated by incredibly stupid idiots, who don't have any sense of what a good map is. :(
( Or, probably more likely, they're just content doing "me too" posts instead of trying to list interesting ones. :@ )