One of the pitfalls of having so many options to store your data in the cloud is that you end up with files and documents spread across a dozen different sites. It gets difficult to remember where anything is saved since you can't search them all at once. Findo aims to change that. Findo, in simplest terms, is a search assistant. You give it access to whatever accounts you want to be searched, and then it indexes your accounts so that you can search for anything. That means emails, files, documents -- whatever you have stored on a variety of services. For example, I have a ton of stuff just saved in my Gmail account, but I also use Evernote to write and have documents on Google Drive. It's actually a little absurd; there are probably other storage services that I don't even remember using. Findo consolidates all that noise. It supports Gmail, Outlook.com, Google Drive, Dropbox, OneDrive, Evernote, iCloud Mail and a few others. And you can use it anywhere. Findo is available on the web, but also they also have apps for iOS, Windows and Mac, as well as Chrome and Firefox extensions.
You can get started on the web for free, but it's actually a subscription service. The iOS app says a monthly "advanced" subscription is $US4.99 ($7), which apparently indexes the past six months of your files, or $US9.99 ($13) to index your entire history. (Annoyingly, it's not clear if that fee only applies to the iOS app -- the web version appears to be free but there's no clear answer on their site). That's a little steep but certainly worth is for some people.