The community of user is stil difficult to measure. As SWTBot is a small and simple project, there is not much Q&A or comments from users about it. However, there are regular (a few per month) questions from users on SWTBot's forum or StackOverflow.
SWTBot doesn't really have "adopters" as it's meant to be a "business" component embedded in 3rd-party apps. It's also not meant to be extensible. The only adopter I'm aware of is Red Deer project, that uses the SWTBot Generator framework with some success.
However, SWTBot has a growing amount of contributors, with more and more diversity.. They provide good quality patches. Some of them were made committers as they show the necessary skills. A lot of collaboration between the various contributors happen on Gerrit reviews. A project co-lead was elected.