Show HN: Simplified interface for old people.
kwkster.com
A simple way to leverage some social networking tools.
kwkster.com
However, if you're going for a general idea of "big icons/minimal description" then I think you might have something cool to start with.
I would think it would be much more useful to write out "Twitter - This is the site that lets you post short messages or read short messages posted by friends and celebrities"