The official blog announcing the feature has gone out, this competition is now closed.
The Stack Snippet feature is now live. When you ask, or answer a question, click this button:
A birdie whispered in my ear that, since Code Review is the first site to have the feature enabled, that a good use-case of the Stack Snippets may well find its way into the official announcement and/or help page, when that happens.
So, make it good!
We can vote on answers that we think showcase the feature well, and perhaps that will influence any decisions for inclusion in the official help, etc.