Thats a pretty good guess late 2000 actually. Keep in mind that most people on b-net belive they have been there longer than they have. I attached a screen shot of my main maps folder sorted by date. This proves I have been making maps since late 2000. (of course i made war2 maps before that) lol want me to dig out the dates on those lol.
My favorate map maker . . . thats a tough one. I would have to say Ither Tuxedo Templar or EvilDrone(U). Tuxedo Templar is not only really good but he also is creative and what i admire about him the most is his increadable modivation to finish things. Evildrone is pretty much the same, maybe with a little more since of what makes a map play well.
Most influanced SC Community, well defently not me although i do belive i played a larger roll than most. I would have to say original creators of the basic genras. First Defence i belive was Lurker defence old 5 island maps where everyone had there own units and you ALWAYS won, I belive that was created by Mystic. Ghost[Yoon] with Turret D, Big-Fat-Homo with First Maxtrix, Heroic-SCV for first "obstical map", KckKryptonite for coining the word Bound and making the first one of those. Also i can't forget GoldenUrg Creator of GUedit and SC Chess.
I however don't have anything that large to say i influenced and alot of it is evolved ideas. For example I made the first known explotion Obstical in the map The Rock, Later used by my good friend at the time KckKryptonite in his first bound (first obstical map witch featured explotion obstical). I came up with the idea for dodge the larva (however sugniffigant you might consider that). And recently The whole mini map Image Fad I started. Also Most of what the clan (U) is today I played a large roll in createing. Although i didn't create (U) orriginally, Kamikaze and I created the clan that there is today.
I hate saying this stuff cause it makes me sound arrogant, maybe I am, sorry.