RTB 1 was a total conversion mod for Blockland v0002 (Often referred to as Alpha Blockland). It added many things for the alpha that you see in Retail today, like saving/loading, minigames, bots, doors, vehicles and more. RTB spawned a bunch of other people to make other conversion mods such as TBM (Which everyone hated), SFM (A total DM version) and AiO (Some mod that no one cares about.). Basically, RTB 1 made Alpha more fun.
When Retail was released, this caused what I call The Great Divide. Almost all of the people bought retail immediately and you can still see them on the forums (Facechild, Randy, etc. ). Some bought retail with no knowledge of 0002 (You, other people etc. ). Some didn't like retail for awhile, got to use someone elses key for a bit and then enjoyed it enough to buy it (Me, MrCookie, etc. people), while some people refused to play Retail, insisted on calling it Rephail or richardphail, and tried to make their own mod for 0002 but failed in development of it, stopped playing 0002 and played other games ( (RW), [PYRO], [ION] ). Some people just went "WTF?" and went to ROBLOX (Thank god, no one.)