I think it'd be a nice addition to have Guild Master, Officer, Recruiter or Member next to the guild name in your in-game profile. They could be abbreviated of course for space constraints, and a check box in options to hide that position if so desired.

May be useful for those who may not frequent the forums (thereby not reading guild threads), that way they could address a recruiter if they were interested. Could also be useful in reporting inappropriate behavior (begging, scamming, etc.) to an officer or GM by being able to identify them.

And sure - membership info can and should be given by any guild member, but those players in the know could address the proper parties appropriately.