Chart, Diagram, and Flowchart Tools

http://www.smashingapps.com/2011/08/26/45-free-online-tools-to-create-charts-diagrams-and-flowcharts.html

Requirements:

1. Infinitely scalable: users and number of documents
2. Realtime, cloud, embeddable, automatically updating

Evaluating:

1. http://www.jgraph.com/index.html and https://www.draw.io/?fileId=0B7pE5Y9PpJCXbEFMSGphM21xWFU - does not appear to have collaborative online feature in free version.
2. http://www.lovelycharts.com/ - only premium appears to have collaborative feature
3. http://flowchart.com/ - requested join invitation
4. https://bubbl.us/ - team is paid; not clear if team is realtime collaborative
5. https://cacoo.com/ - only 25 users
6. https://www.lucidchart.com/?utm_expid=39895073-40.cV9vRzTxQMmhllfotWNAPA.0&utm_referrer=http%3A%2F%2Fwww.smashingapps.com%2F2011%2F08%2F26%2F45-free-online-tools-to-create-charts-diagrams-and-flowcharts.html
7. http://www.yworks.com/en/products_yed_about.htm