[quote=@shylarah]it looks like I understand the basics, but what is support vs. utility?[/quote]
Utility is perhaps an archaic term that is lesser known, but in the sense of how I came to be familiar with it I can explain. Utility represents people who orient on enchantment buffs, utility spells, general utility functions such as trap expertise, and so forth. Here is what someone on another forum posted about utility:

[indent][i]Are abilities or spells that are meant to inflict status effects (sometimes multiple) on targets. Think for instance a root combined with increased damage on the target of that root for the duration of the root. Obviously the root wouldn't be unbreakable, and obviously it shouldn't last too long. Perhaps this kind of a root has a certain number of counters that are used when damage is dealt to the rooted creature.[/i][/indent]
This [url=http://www.mmorpg.com/gamelist.cfm/game/15/feature/6091/The-Role-of-Utility.html/page/1]article[/url] may also help.