Norton Antibot protects against the dreaded botnet which is a evolving creation.  You cannot protect your computer from bots sufficiently with normal antivirus software. The reason is because bots don't have signatures.  Bots go to sleep and wake up.  Antivirus software packages don't look for this type of behavior.  Norton Antibot proactively looks for strange behavior.

In conclusion, the reason you need norton antibot is to protect your computer from the rising threat of botnets which can not be identified by standard antivirus software. Norton Antibot augments antivirus software.

Olan Butler - Technology Specialist - Computer Services