|SNMP, or the simple network management protocol, is used to aid in management of machines over the network. This can be a powerful method of monitoring and administering a set of networked machines. If you use network management software to maintain the computers on your network then you should audit the way in which SNMP is used by that software. You should (1) use SNMPv3 wherever possible, (2) set restrictive access control lists, and (3) block SNMP traffic at your firewall. Otherwise it makes sense to disable the SNMP daemons.
The average home user has no reason to run these daemons and depending on their default configuration, they could be a major security risk. Alternatively if configured correctly, and used in conjunction with management software these daemons could be used to dramatically improve accessibility and response time to problems when they occur.
Things known to not work if this is disabled:
Network management software, such as HP Openview, which relies on SNMP|