There are various forms of collaboration, from interviews with marketing experts to the creation of round-up articles in which several contributors give their opinions. The ultimate goal of these collaborations is for UK Phone Number experts to share the content in their communities, whether through their social networks, newsletters, etc., to reach their followers.
So, once you've published the interview or roundup, it's a good idea to send them a message reminding them that it's now available to share if they want. Otherwise, there is a risk that it will go unnoticed or that the people involved will not even realize that they can share it.