Many of you have probably already seen and used Google Instant search. (If you haven't, just go to google.com and start typing. Then bask in the glow.) But now Webyog, creators of the MySQL manager and admin tool SQLyog, have put together an extension for Firefox and Chrome to allow as-you-type searching within your Gmail account. It's called CloudMagic.
Having installed it myself, I'm generally pleased with the results. The searching is much, much faster, and if all I'm trying to do is find a single message or thread, it's definitely the way to go. But if I'm looking for a group of emails to batch-label or -archive, CloudMagic can't help me; it doesn't seem to have that functionality.* Plus there's the fact that, almost a day after I installed it, it still seems to be indexing my emails. (Though I noticed the example account page in the video says the same thing for both accounts, so maybe I'm mistaking their meaning. Unfortunately, their diagnostic tool is somewhat cryptic.)
But with those caveats, it seems like an application with serious potential. As the video notes, they're also planning expanding the application's functionality to include Google Docs and other webmail providers. So if you're using Gmail, take a moment to check out CloudMagic.
* Something I'm sure Google will correct if and when they decide to just purchase the app. Or the company. Or the city of Bengaluru, India.