I seriously don't care for crossposting.
The reason, someone talks smack at Site A, then it's crossposted on Site B, then Site B's users register at Site A to tell Site A what they think about their post. Site A's users register at Site B and it swirls around the toilet bowl with the partially digested corn and other post digestive organic matter.
Besides, users that register with a single agenda give me a rash.