Despite Prophet being designed for "offline" replication, Prophet's (and SD's) developers are nearly constantly online. You can usually find us on IRC and can always contact us by email.
Prophet's developers hang out on #prophet on irc.oftc.net.
If you're looking for something a little more asynchronous than IRC, electronic mail is always a reasonable option. You can sign up for the Prophet mailing list or browse the list archives over at Best Practical's mailing list server. There's also an SD list for SD-specific discussion.