Ext. Link: Check rowdii.com for websites
“Rowdii adds a forum next to every website in the world, so you can discuss different products, services or web content as well as share files… Rowdii is the only web tool that allows users to link websites together, so you can easily discover interesting sites related to the one you are viewing.”

Ext.Link: librarything.com for books

Other Researchers

Brief Biographies: needs to be edited and sorted

video tools

Some Notes on Math

Some Notes on Maxwell's equations

Notes on gravity waves

Notes on other researchers

Great links