If you’re often interrupted while reading an article, because of lack of proper explained things, and use a search engine to find more information about the concept. KallOut a Windows application addresses this problem that bring "selection-based search" to any web page, email, presentation, document, spreadsheet or PDF reader. Instead of copying text and then pasting it into a browser whenever you want more information, you just select some text and obtain some useful information in a mini-browser.

Download

Source:→ Google System