Gmail may not be the most used mail app today. But Yahoo knows that with that compelling an application, they are going to steadily lose out to Gmail sooner than later. So, not long ago, Yahoo bought Oddpost, a web based innovative email service. Logging in today, I saw their 'Coming Soon' ad for Yahoo Mail Beta and checked out on the overview. Looks cool. You can get on their A-list. That's probably the initial testing list. Awaiting their invite!
Now that should be a big headache for Google to contend with.