Most of us have trouble remembering what sites we’ve registered for and which e-mail account or password we used in the registration. That means many of us are wondering if our confidential info was exposed in the recent hack of Gawker and its affiliated sites.

Thanks to the folks at Slate, there’s a neat little online tool that can check for you. The widget lets you enter an e-mail address that it then compares against the hacked database. You can enter as many e-mail addresses as you like, the widget will check them all — but not at the same time of course.

The Gawker hack illustrates an important security problem for all users who want to keep their confidential info confidential: Using the same password for all online accounts has its perils. If one site is hacked, then criminals have the keys to your private — and often financial — kingdom.

Exposure of the Gawker data also pointed out how insecure many users passwords are. A Wall Street Journal story lists the most often used words and phrases. Top of the list: 123456. Arghhhhhh!

Ironically, one of the best guides to creating an online password can be found on LifeHacker, a Gawker website.

Tags: Gawker, LifeHacker, passwords, Slate