The Debian Packages Tracking System has a great feature: you can subscribe to packages that matter to you, and be informed of all uploads, bugs, testing migrations, etc.
However, when (co-)maintaining a lot of packages, it is easy to forget to subscribe. And then you might miss important information about your packages (uploaders don’t receive bugmail by default, for example).
Since PTS subscriptions are now imported into Ultimate Debian Database, it is easy to find out if you missed some subscriptions. It’s just a matter of going to http://udd.debian.org/cgi-bin/pts-check.cgi and entering your email!
And for those concerned with privacy, it should be noted that the unauthenticated access to UDD only gives you the hash of the subscribers’ emails. You need to be a DD, and use the guestdd account to see the email addresses (which DDs can already see on master.d.o).