In a previous life I was ‘the diagram guy’,  the chap who chatted to someone about an idea and had to convert a concept into an architectural diagram. I prided myself on my ability to talk to someone on the phone, grasp the idea, and turn a draft diagram around in a few minutes,  saying "you mean something like this?".
Network diagrams,  software architectures,  market life-cycle graphs, you name it, they were all grist to my mill.

I still do that kind of thing now, on occasion. If you're in a similar position, Dabbleboard may prove a lifesaver.
 
It’s a shared collaborative white board. There are no shortage of those out there, but one that is designed in such a way to be effortlessly powerful. Using the UI, I think to myself - why didn’t anyone else think of doing it that way. 

The usual problem with mouse-based whiteboarding is that the results usually look like those of a 3 year-old. While it is possible to get that niave look, by using the freehand mode,  in the alternative mode Dabbleboard will try to guess the shape you’re drawing and clean it up.  Something that looks vaguely squarish, rectangular or triangular all get instantly converted into a clean vector shapes that can be  resized,  repositioned and transformed. It keeps drawing very fluid… and fast. I am particularly fond of the duplication function. Click on a shape and various ‘handles’ with different functions appear around it. One of these, lets you copy a figure. simply by dragging on the handle. This is a nice example of how a tiny bit of usabilty work can give a piece of software an undefinable feeling of class. Copy and Paste isn’t hard, ctrl-drag to copy is nice, but this drag-to-copy method is lovely.

Other nice features? A simple API which lets you embed a whiteboard into any page and the ability to construct (and publicly share) libraries of shapes, such as UI widgets.
Here's a demo:

At this point I would normally indulge in a bit of constructive criticism, but there’s really not much to add. It’s fast, slick and nice to use. It’s also free. Developer Zohair Hyder says that there will be a paid version with corporate-friendly features SSL, access control, etc.) in the future.  But the free version will remain, with at least the same feature-set as we see today.