Not quite IRC, G+, or Roll20, but I've been thinking for a while about whether it would be good/bad/indifferent to place more emphasis on the abstract nature of D&D combat.
It would be possible to resolve most combats with just one set (or relatively few sets) of instructions from each player. The ref could go away and resolve the whole combat in one go, and then post a summary of the main events and the overall outcome, rather than the typical blow by blow account we're more accustomed to.
A combat would certainly be resolved very quickly--but perhaps it might all be over
too quickly. Especially in the event that it goes badly for the players

[f=32]
Golgildir the Elf Medium (MV 12", AC 9, HD 1, hp 1/1, AL N) great cloak,
lantern; spells: color spray; scrolls: sleep, sleep, charm person
Hirelings: Georges;
torch[/f]