That's an excellent program. I downloaded it per your suggestion, but I really wanted a web based version. Thank you though, I will find many uses for this program as well.
Dot itself is also a command line tool, so it's easy to make documents and presentations with TeX that have text-format diagrams in the dot language. You can also do things like generate call graphs for programs, or parse log files into sequence diagrams by parsing input somehow and generating dot files.
i have a script that reads django models.py files and constructs OmniGraffle object models. hmm...could be neat to go the other way since i usually make the diagrams first...i wrote the script because once the main idea is figured out then i'll make lots of iterative changes in the code and not want to update the diagram so carefully..
i'm still working out the details. but i'll post here as soon as that's all good :-)
not sure if anyone else is interested, i guess.
