I’m not sure what you mean by a “cool way” to do this. But there are a variety of ways to accomplish this depending on your exact needs.
They key is: Do you have a membership login already set up? (e.g. Sitelok).
If you have a formal membership system in place then you can probably accomplish what you want depending on the specific features offered by that system. For example, Sitelok has an extra plugin for SSO to Disqus. Thus you could easily create a page, or portion of a page, where folks make these contributions via Disqus. (Their contributions will be “private” and they’ll assume the name given to them by Sitelok.) They can also add a personalized avatar via Sitelok’s Blab plugin.
If you have a CMS in place (e.g Armadillo) then you can set things up so each member gets a dedicated stack area on a page that they can tweak.
But I’m not sure if you are starting with membership software, a CMS, both, or neither. Nor do I even want to guess at what another person means by “cool” (e.g. some people thought Lionel Ritchie was cool: an unfathomable and incomprehensible thought.)