I actually had this idea 4.5 years ago. No joke! I finally got around to actually doing it. There are reasons this doesn't work as a startup, but as a side project, it could thrive.
We're going to blog about it soon on http://blog.yesgraph.com along with some other projects. This isn't the most impressive imho, but the best understood by this community.
The design was done by Guillermo Torres at YesGraph. I made a working app and he did the visual design and UI engineering in that 30 hours. I combined them last night and pushed the update today.
YesGraph
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YesGraph
SandStorm
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YesGraph