I have an idea where users typed in their username and password (or multiple username and password combinations) and the app returned a yes/no for the top 100 (1000?) websites out there.<p>I "register/sign up" for 100's of services/products a year and at this point do not know who or where they are. I think it would be amazing to have a dashboard of every place I've ever logged into. Similar to the "app settings" page on Facebook/Twitter<p>http://www.facebook.com/settings/?tab=applications<p>Short of a password manager (1password etc), I don't believe this service exists, and certainly not one that automates logging in to 1000's of websites on your behalf.
To be honest, I like the idea of it to some degree (very minor), but knowing me I probably wouldn't actually use it. I don't even go in to check which services I've granted access to via Twitter, Facebook, or my Google account.<p>That said, I already use a password manager so I don't believe I'm the target audience for the purpose behind this app. Truthfully at most, I'd maybe look at it once and never bother again. But even then I probably wouldn't if it required me to punch in my password to check. This is especially true for people who use unique passwords.
This only works if you use a small subset of usernames and passwords. A person who actually wanted to do this in a secure way would use a password manager and just record every username and password there.