LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
Viral Loops - Viral Loops is a viral and referral marketing platform to launch ranking competitions, sweepstakes, pre-launch and referral programs.
draw.io - Online diagramming application
Referral Candy - Run a fully automated, customizable and easy to integrate referral program for ecommerce.
yEd - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.
UpViral - Referral marketing platform enables anyone in running effective and profitable viral marketing campaigns – in minutes.