I’ve slowly started moving to online document management using Google Documents. Unfortunately they lack a Diagram utility (like visio) of any kind and so I went searching for one. Luckily enough the people at Gliffy agree. The Web is a perfect platform for such a collaborative sort of document like the diagrams you can create with Visio. At this point in time they don’t support the ability to import Visio or other Diagram type documents, but just the ability to use an online tool to build diagrams so that they can be shared and collaborated on is awesome.
Gliffy also allows the diagrams to be embedded anywhere on the web as long as they’re public. You can also get many different sizes including a thumbnail version. Private documents are provided as well but that requires a paid subscription to their service.
The service itself is very responsive and in fact allows building diagrams much quicker than doing so in clunky bloated client side applications such as Visio. As with any web application one of the key benefits is also that your created document is available anywhere and no client-side software is needed. An example I threw together quickly is below.