Slack bot users: https://api.slack.com/bot-users
Slack incoming webhooks: https://api.slack.com/incoming-webhooks
A list of slack apps/bots: https://slack.com/apps
A few examples of what a slackbot for Xenforo could do:
- Notify when a new user registers
- Notify user moderation
- Notify when @X gets tagged
- Notify about new entries to the error log
- Setup milestones - "yay, you just reached X registered members"
- Report statistics "800 users currently online"
- Ban/report a user by typing /ban or /report username
Not sure what's possible, but any support would be super cool to have.