On a site with open membership, DBR automatically results in the user becoming a site member and watcher of the site. Open sites are "sticky" and acquire all new registered users.
Again, I don't think this is a good idea. The default action should be that all new sites joined by a user are NOT watched. If they find themselves continuously clicking on 'watch site' then they can set it to automatically do so in their user settings.
If I came across a website and joined, then started being spammed with emails from edit changes, I'd do two things:
- Block the domain from sending me mails (send them straight to the spam folder and "report spam" in Gmail)
- Never visit the website again
This is exactly the same situation as Wikidot puts users into.
Auto-watching is useful for websites that I own, but except for me being a part of the community now, I wouldn't want to watch any other sites. I'd rather just visit them when I have time and read the news, blog, etc. for updates