My company uses groups to let people opt-in and opt-out of things like new Windows builds. To do so, people go to our DL portal, find the group and join it. A much easier way for them to do so would be via "Deep links", where one visit to a specifically-crafted URL would immediately file a JOIN request (instead of the user needing to search for the group, click Join etc). This feature is common in many other resource-management apps like Service Now, Microsoft FIM and others.
For example, a URL could be:
Please sign in to leave a comment.