Evernote

http://www.evernote.com

Evernote is a web service and software application that allows users to collect notes and information, then access that information from any computer quickly and easily. It supports touch and tablet screens with handwriting recognition.  Evernote lets you tag notes, drag and drop them into folders, and even perform advanced searches for content within a note and save that search as a custom filter.

You can search the contents of any note from any device you're using with Evernote. It even searches text within images by scanning and analyzing for any image for text—including pictures from web pages, documents, photos, screenshots, or cameraphone pictures you upload.  If you are a hand-writing person, then you are also in luck since Evernote has support for digital ink and will recognize your hand-written words and build them into its search.

Evernote is free to use, but a premium service is also available, which costs $5 per month or $45 per year. The premium service features faster word recognition in images, greater security, and a larger per-month upload limit to Evernote's online servers.