Vague = Valueless
“The very first law in advertising is to avoid the concrete promise and cultivate the delightfully vague.”
Perhaps in mass media, 30-second-or-less advertising, this applies. But not in the real world.
Most communications need specificity. This counts double in social media, where messages are limited by technology and providers (like Twitter’s 140 character cut-off) or by the scavenger nature of most social media consumers.
Vagueness leads to disinterest, which leads to an inattentive or diminishing audience, which leads to a not-for-profit status.
Treat each outbound communication like it was your only chance to talk with the intended audience, and make it mean something to them. If the communication is designed to lead them to more communications (i.e., a Tweet and link to a content page), then make sure the terminal content has meaning too.