This summer’s most popular web site at our place is with the weather forecast.  Yr just hit a billion weather forecasts since the start in 2007 (given that the site is in mainly in Norwegian, and there are only 4.8 million Norwegians, this is amazing).

One of the main factors in the success of is their open access to data sources. hands out XML streams (and GRIB for the oceanic) for 7 million sites world wide, and they provide access to all data from all Norwegian weather stations.  Scripts for including as a gadget on your own web site are available, with good user instructions. In addition to a good end user interface this helps build a reliable site for weather information.

My advice to other public agencies: provide data that may be presented, reused and reconstructed – and build a simple interface to your own information.