In one of my previous posts, we saw how you can programmatically add a document to a Delve Board with the REST API. This is a follow up post to that in which we will see how to Follow or Unfollow a Delve board with the REST API. If you haven't already seen the previous article, I suggest you take a look at it because it explains how Delve works under the hood and how you can integrate Delve into your custom Office 365 solutions.
Please bear in mind that since Delve utilizes search internally, you will have to wait for a search crawl to take place in Office 365 before you can see results of the REST operation.
I have used JavaScript and the jQuery.ajax function to make calls to the Signals API. But you can use a variety of other options which support REST.
So without much further ado, here is the code to follow or unfollow a board in Delve: