In a matter of seconds, a visitor will decide whether to tentatively accept or reject your community's group identity.
If they reject it, they leave. That's it.
If they accept it, they go deeper into the community. They click the next page. They complete the registration process. They make their first contribution. They begin to assume the group identity for themselves. They begin to feel the group represents them. What happens to the community, happens to them.
Some communities have a clear, strong, identity. It's apparent in the name, the topic, the design, the type of discussions, and how members interact. The Rock and Roll Tribe pulls off the cool middle-aged rockers vibe to perfection. The tag-line reads: "F*ck the middle age, lets rock". It doesn't take long to determine if it represents you.
We need good cues to discover the group identity. It can be reflected of the tone of copy on the website, the design of the community, the discussions taking place and any visible information about the community.
You can guess where this is going. It's good to have a strong identity that most will love, but some will reject, than a weak identity. You need to craft that identity. You need to create those cues that guide others to this community identity.
Who is your community going to be?
Show a clear personality in your web copy. Set the early tone for how members interact with each other. Highlight what sorts of discussions the communtiy has. And, if you need graphical help, use it. If you're polite caring, then push the polite and caring angle. If you're joking and jesting, then push that angle too.
Proactively craft a strong group identity.