Target audience is very important in design, but on this site we have a pretty bad history of not mentioning audience often, and almost never tagging for audience.
In the past I've created the older-users tag to mark questions targeting older audience, but it hasn't had much acceptance.
Obviously there's no need for a "general audience" tag or such for questions that don't specifically relate to a target audience, but I'm thinking tags like children older-users could be useful; designing for these users is demonstrably different than other users, and there's certain relevant expertise to designing for these groups.
Should we create and encourage the use of audience tags? What are relevant audience tags that can be applied to current questions?