Chrome only: Google Chrome extension Popchrom creates shortcuts that expand text snippets into full paragraphs and phrases, automating anything from creating a signature to using canned email responses to save yourself some time.
Once you've installed the extension, just head into the Tools menu -> Extensions, and then click on the Options button on the right of the Popchrom extension. From there you can setup your text strings and what they will expand to, and the help page explains how to use a few replacement parameters to specify particular dates as part of your string. Using the text expansion is as easy as typing in the string and using Ctrl+Space to expand it — for instance, using the example in the screenshot, if you typed in "lh" and hit Ctrl+Space, Popchrom would replace it with "lifehacker".
The extension still has a few bugs and doesn't yet work in Google Docs or some other rich text editing environments, but it does work perfectly in Gmail and many other places, and could really save you some time while clearing out your inbox.