It's the, er, epicenter of the digital universe, so the web sites are myriad, informative, and usually innovative. Here are some of the best:
The San Francisco Chronicle's online component is sassy, fun, and full of local events and opinions. Where to go if you want to know what's PC to say about the As and the Giants when you meet a local.
The San Francisco Bay Guardian online
An outside guide to SF—outdoor adventure
Sally's Place 'Ports of Call,' is a very informative site, with restaurant reviews, shopping tips (by area and by type), hotels, activities for kids, Gay San Francisco listings, nightclub listings—everything. Not beautiful, but lots of scoop.
The Rough Guide for San Francisco online—incredibly useful, esp. for young travelers on a budget. Great user tips on bars, cafes, restaurants, deals, excerpts from writers writing about San Francisco.
San Francisco Underground Travel is a site that promises to keep you away from 'lame-o' tourist traps and give you the city tour that a local friend might. Very conversational and opinionated.
Virtually San Francisco—great links to activities, including those in surrounding communities and areas (the Santa Cruz rollercoaster, the Napa Valley wineries, Big Sur and Carmel
The Exploratorium online has created amazing site that's perfect for enticing kids into excitement about a visit to the city (and this captivating museum). You can dissect a cow's eye online. Grody.
SF's Museum of Modern Art's website, as well as the museum itself, is worth visiting for aesthetic pleasure.
The Golden Gate Bridge's site has all sorts of info and some glorious pictures of its erection. Wow.
For the squeamish and the curious brave—the USGS's site chronicling the Great Earthquake of 1906 with photographs and seismic graphs and reports about the quake.
A list of speedtraps in the SF area is a must for those who're renting cars
The BART (Bay Area Rapid Transit) site, with information about different services in the Bay area, is a great way to get oriented.