A browser is software, just like a word-processing or spreadsheet program, only instead of cranking out pie charts or memos, a browser enables you to see Web pages. Mosaic was the first browser, while Netscape and Internet Explorer are the most commonly used nowadays. The advent of browsers transformed the Internet - formerly a dry, text-based thing only a government official or academician could love - into the colorful, user-friendly Web we know and use.

How it works: Browsers take text files written in HTML (which is the coding language that gussies up plain-old text with images, sound clips, and links to other Web pages) and assemble all the relevant pieces into one colorful, easy-to-digest page. Browsers can also host a variety of additional Internet fun: email, chat rooms, newsgroups, online gaming, and more.