I've been playing with RocketChat for a while and it's a fairly decent Slack alternative that's under active development. If you want to go off the record in a private chat, click the button, wait for the other person to confirm, and your conversation is now end to end encrypted. It's fairly easy to install if you want to self host, and they offer hosted versions too. I'm a fan.

I'll give a +1 for dspam. I run it on a couple of accounts via procmail under qmail and it works really well. When spam gets through to my inbox I just move it to a spam training folder and an hourly cron task passes that folder's contents back to dspam for training.