Diving into a rich and overwhelming social network like Twitter can be difficult. I know of many teachers and academic-minded people who are still unsure about the merits of the tool or are simply unsure where to start. The following 10 (+1 bonus!) beginner's guides to Twitter each do a tremendous job at informing without confusing.
Bootstrap is a toolkit from Twitter designed to kickstart development of webapps and sites. It includes base CSS and HTML for typography, forms, buttons, tables, grids, navigation, and more.
Nerd alert: Bootstrap is built with Less and was designed to work out of the gate with modern browsers in mind.