yUML

Just linked yUML to my blog. I like that service.
There are also few articles about it here.

There are next few yUML samples:

[Document]<0..*-1[DocumentTemplate],[DocumentTemplate]-^[Template]

[DocumentTemplate]-^[Template],[ReportTemplate]-^[Template|-name;-author;-location|open();save();remove()],[FigureTemplate]-^[Template]

[Administrator]-(Create Template),[Administrator]-(Create Document)

And now Scruffy variant:

[Document]<0..*-1[DocumentTemplate],[DocumentTemplate]-^[Template],[ReportTemplate]-^[Template],[FigureTemplate]-^[Template],[Template]->[Author|firstName;lastName],[Template]->[Resource|fileName;type;version]

[Ruslan]-(Create Article), [Ruslan]-(Edit Article),
[Ruslan]-(Write Comments)

Looks great, isn't it?