The trust relationship is required for gadgets that access restricted data from the external web application.
See how to configure OAuth or Trusted Applications Authentication, using Application Links.
Need a feed widget to display your latest blog posts, tweets, Vimeo or You Tube uploads, Picasa images?
You can add all the gadgets from your JIRA, Bamboo, Fish Eye or Crucible site – or from another Confluence site – to your Confluence gadget directory.
If the external web application provides anonymous access to all the data you need in the gadgets, then you do not need a trust relationship.
For example, if your gadgets will retrieve data from then you will need a trust relationship between Confluence and JIRA.
This is necessary for applications and websites that do not support gadget subscription, and for applications where you cannot establish a trusted relationship via Application Links.
People can then pick and choose the gadgets to add to their Confluence pages.
If you cannot subscribe to an application's gadgets, you will need to register the gadgets one by one.