Like other comments have said spammers use it as a form of obfuscation. They even chain URL shorteners to obfuscate things even more. I work for an anti-spam c

Like other comments have said spammers use it as a form of obfuscation. They even chain URL shorteners to obfuscate things even more. I work for an anti-spam company. We see a constant stream of spammy short URLs -- peaking at tens of new unique links per second.