Billygoat is an anti-spam bot. He is easily offended. So no spam, unless it's the tasty variety, and it's best not to poke him either.
Note: The times here are best guesses, and are wrong.
Sub-note: Apparently, saying the following results in a temporary kick/ban. "If a blogger farts, does it pollute?" Note to AI researchers, intransigent behavior is a definitive sign of intelligence.
HAHA DISREGARD THAT I STOPWORDS.
 Two minute ban
- Saying "candlejack"
- Saying "you just lost the game" or "you lose the game" - possibly also other variants
- Peeing in bucket
- Sending beep characters (^G)
- I'm in space - (you're not in space!)
 Five minute ban
- Attempting to lure another into poking the goat by obvious means.
- More than seventy characters of capitals on a line.
- Using a stopworded word.
 Potentially Very Long Ban
- Poking billygoat or using billygoat and prod or poke in the same sentence. He doesn't like it, we don't like it, you may be banned for up to 24 hours. Please note that prodding the goat is the same as poking him.
- "NIGGERS", all caps, anywhere on a line
- "feces" or any synonym on its own line
- "jews" three times anywhere on the same line
Although you can avoid offending billygoat by avoiding the stopwords or actions above, you may still get, if unlucky, trapped in an endless loop of billygoat kicks.
For those who like examples, one can be found in xkcdb quote #8837.