We don't necessarily announce all our behind the scenes processes, but the Team does actively work on removing inactive members. We have several ways this happens.
One is the Unresponsive Profile Manager process, which has a few steps in place to make sure we don't close accounts for people like some have mentioned, who just need to be away for a period. I'll let Paul explain that a little more since he's the Team member who takes care of those.
We have an automated process which tracks email addresses from accounts which have started bouncing. After the email address has been returning mail to us undelivered for about a month and half, the person's newsletters get turned off and we post a message on the member's profile to let them know that we'll be closing the account if no action is taken. Usually, nothing happens on their end and we close the account, because they're genuinely no longer active. This process closes several accounts a day. Since we initiated it, we've had a handful of people who didn't realize their mail was bouncing or that they hadn't updated their WikiTree email address, and we helped them change it so they were available for collaboration again. The great majority of bouncing email accounts just aren't interested anymore.
The other thing we monitor is people who are marking our mail as spam. This one is a bit trickier. We get numerous reports each day that someone thinks our mail is not genuine, but instead is spam. We contact these people to make sure it wasn't an accident, as I know I personally have had WikiTree end up in my Spam folder and had to move it out because I certainly don't want it there. If we don't hear from them and we continue to receive the reports, their account is eventually closed. This also results in a number of closures each day.
Between the three processes we have in place, you'd be surprised with the constant flow of accounts that are reduced to limited watchlists or closed. To clarify on some of the responses people have mentioned, we are very serious about private profiles, so we try to look at watchlists to make sure private profiles are not orphaned but deleted, unless someone has specifically requested access to the profile or there are others on the watchlist who can manage it. Otherwise, anything that can be opened and orphaned, is, so that members can source and add family, and generally improve the tree.
It's hard to put a time limit on how long people are gone to decide they're no longer active. I see people regularly come back after several years, realizing they only now have time they hoped they had when they signed up, or they better understand research now. Paul's process has steps that help make sure we don't just close those accounts, as he reaches out to make sure those people understand what happens if they can't be reached. It seems like a hassle to some of you, but for those who have been part of the process on the other side, we need to be respectful and aware of the fact that real lives outside WikiTree draw us away. Tweaks may be beneficial, but we'd need to tread very carefully in removing people from WikiTree or reducing watchlists. We can't just put those back in place. It means nearly starting over in many cases.