I don't think "toon" was used in UO. At least, not when I was playing on Baja in '98-'99.
Never heard it in UO either, I heard it in CoH too, especially in the US servers where it was the "standard" way to call a character (EU server not so much). I heard someone using in Ragnarok Online too but it was the exception.
Back on the thread... our clerics often use it to fill up empty levels, especially healbots, but we never used it in an offensive capacity. The main uses were:
1. Runes of Revivify, since they can be used without UMD by everyone and the price isn't that higher than a scroll.
2. BUFFING ARMBANDS, basically a line of runes that worked times/day strapped to our character arms/scabbards/whatever, each with a buff in it so we could full buff as a part of a move action.
XP costs were ofc split among the party (who wants a rune pays the xp and money to the crafter) using the spells in PHB2 Web Enhancement.
It also gets suggested on the boards, as a matter of fact someone suggested it to me no more than 2 days ago on my Archer Cleric thread.