The Internet wasn't invented for RealClimate specifically, but it's hard to imagine a site more in line with the Web's original purpose: scientific communication. An assembly of climate researchers gives readers what's lacking virtually everywhere else straightforward presentation of the physical evidence for global warming, discussed with patience, precision and rigor, and, quite often, length, such as in a 2,300-word evisceration of Michael Crichton's work of fiction, State of Fear. Never mind that the Sun appears to be falling into the ocean in RealClimate's banner.
Sample RealClimate post: [Crichton] also gives us his estimate, ~0.8 C for the global warming that will occur over the next century and claims that, since models differ by 400% in their estimates, his guess is as good as theirs. This is not true. The current batch of models have a mean climate sensitivity of about 3 C to doubled CO2 (and range between 2.5 and 4.0 degrees)..., i.e., an uncertainty of about 30%. As discussed above, the biggest uncertainties about the future are the economics, technology and rate of development going forward.