Websites supporting Google-like search operators

Without the ability to search and filter results, the knowledge contained in large sites could as well be hidden. I frequently use Google search operators like site: and filetype: and they save me a lot of time.

I heavily use the Stack Overflow forum and bookmark all the interesting questions & answers. Till I figured that there was a search operator called infavorites:mine (or any user id) which returns search keyword matches for only questions that I have favorited, I used to manually look through my list of favorites.

I realized I should compile all the sites I find that provide time-saving search operators along with some documentation for future reference, so here goes the list:

* Google Search
* Bing
* Stack Overflow & Stack Exchange family of sites
* Outlook.com
* Gmail
* Google Drive (lets you search for text in PDF and image files & by describing or naming what's in them!)

work in progress...