That isn't how Snapzu works though, is it? You're a part of the community if the tribe you're following is added to a snap. If /t/gaming is added to every snap of /t/somegame, then nothing has changed.
Here's an example:
I take a screenshot of skyrim and put some text on it, I go to /t/skyrim and post it, crossing it to /t/gaming as well. What's likely to happen is that in Skyrim it will get viewed and appreciated by a larger audience, in /t/gaming, it will get viewed by a larger audience but appreciated by fewer. But this is really just over analyzing. Specific tribes exist for the purpose of being specific for when you want to browse them, big tribes are for when you want to browse the bigger picture. But there's no reason we shouldn't colaborate the 2