Chrome and Safari: You may have dreams of reaching inbox zero, but actually getting there can be a chore. 0Boxer attempts to make the process more fun by creating a social competition out of organizing your inbox.
Here's how it works:
Sign in through your Google account, tying it to 0Boxer.
Grab the 0Boxer extension for either Chrome or Safari.
Head over to Gmail and start organizing your mail. 0Boxer will start assigning you points for your activity, and you'll see a little top bar tracking your progress.
Note: It actually wasn't that straightforward for me because I tried to use a Google Apps account, but I just had to click an extra button to set the login again.
After archiving or deleting a few messages you will earn your first badge and see your stats rise. While 0Boxer keeps you informed with a little bar up top in Gmail, you can always check your full stats via your 0Boxer profile. If you want to see how you're stacking up against others, a daily leaderboard keeps track of the rankings in real time.
0Boxer is available right now for Chrome and Safari (Firefox and others coming soon), completely free. It doesn't necessarily perfectly match up with Merlin Mann's Inbox Zero (they actually call it "zero inbox"), but if you need a little extra motivation to reply to emails and empty your inbox, it's worth a try.