Virtual Tourist Vienna

Virtual Tourist is a guide written by citizen contributors, and I would say that its Vienna Guide is quite good. In the etiquette section, the first issue covered is the Viennese taboo of jay-walking. It's something that every visitor to Vienna should know.

Guide to Boston's Architectural History

For any traveler who wants to get a good apprecation of Boston's architecture throughout the years, iboston.org has a very good site which plainly, yet intelligently discusses the most important buildings in Boston. It includes a lot of excellent photos.