The Locker project has a similar goal but is completely open-source. You can run it on your own server if you don't want to put all your eggs in someone else's basket.

https://github.com/quartzjer/Locker

I have my Facebook profile completely locked down from the outside world, and I make sure that what does get out there under my name is stuff I want out there. I am already wary of Facebook to the point that every-time they change something privacy related I feel like I may as well just delete my profile.

While I am intrigued as to how Greplin works I don't think I would ever want to use it because of the concerns you've stated and I myself agree with.

Check out Redwood, http://redwoodapp.com. It runs on your desktop and searches Google Docs, GMail, and Basecamp. Since there's no server intermediary, it doesn't have the same privacy concerns as greplin.

This article confuses some things but try it. I didn't get it at first either but it's a great idea and crazy easy to use. If you have tons of stuff spread out over multiple social networking sites, there's no easier way to search through your own online history. And our histories are just going to get bigger and bigger.

I can see the privacy concerns but you can select which platforms you want (or don't want) Greplin to have access to, so that's not such a big deal to me. For sites people use professionally, for organizing projects etc this is a great tool.

I looked at the list of platforms, and I did not want Greplin to have access to any of them. For example, GMail already has search, Facebook has confidential personal stuff, and Dropbox has confidential work stuff.