What is JIRA from Atlassian.com ?
JIRA is an interesting system (an Enterprise Form and Workflowsystem) - very stable and with a lot of expansion possibilities, and can be - with an onDemand instance be used for $10 a month.
Read JIRA as a holistic Form and Workflow system
An onDemand (cloud based) has some restrictions regarding plugins, as an alternative option, run the product on a "local" or cloud based server.
Pages
Labels
Blogs
http://blogs.atlassian.com/tag/jira/
https://jirasupport.wordpress.com/
https://jirasupport.wordpress.com
Design API
https://design.atlassian.com/latest/
https://docs.atlassian.com/aui/latest/sandbox/index.html