It might be a good idea to do a survey of reasons why previously active users of the site are now quiet. For me, it was the simple things – I had a hard time navigating the sign-up process, and then when I did get signed up, it was a bit of a pain to get my username and password to work. With the previous forum, once I signed in, I was signed in for almost forever. So, it was easy to just click on the forum bookmark and jump right in.
My experience might not be the same as others, so it would be good to send out an email to everyone who was previously signed up for the old forum and ask for opinions on why they haven’t used the new forum.
While I’ve been in the user experience, cyber security, and app development worlds forever, I definitely notice my behavior falls into the same category that drove me crazy with users in the past. Namely, if something forces me to think about how to navigate something clunky with a site or password, I’ll put it aside and tell myself I’ll come back later – and then I generally never will.