When you've got a question that's strictly factual, a search engine usually does the trick. When the answer would benefit from expertise and opinion, you want to ask a smart human being — or even better, a bunch of them. Quora is a terrific way to find those savvy folk and benefit from their knowledge (and pay back the community by sharing your own insights). It's one of umpteen Q&A sites on the Web — others include Ask.com and Yahoo! Answers — but the quality of the conversation is uncommonly high. The site is especially popular in Silicon Valley, making it a good place for geeky questions like "What is the best bag for commuting via road bike with a laptop?"