Snippets allow you to store and easily reuse TSQL code snippets. To use a snippet, just right-click in the query window and select "Insert Snippet", or you can use the keyboard shortcut Ctrl+K, Ctrl+X.
Snippets are stored as XML files. Once you have snippets created, you can import them, or even create new ones of your own.
This post is for day nineteen of my month-long blog series "A Month of SSMS Tips". I have a landing page for the series at bit.ly/MonthOfSSMS. Please visit this page for an easy place to quickly view all of the other tips in this series.