GOLD (Generic OnLine Diagnostics) allow you to continually test the health of your device without necessarily interrupting service. GOLD can generate SNMP and syslog events (much like EEM).
EEM (Embedded Event Manager) extends GOLD by watching GOLD test results, and allowing you to take additional action based on those results. For example, if a GOLD test fails, EEM can detect that failure, and perform configuration tasks on the switch to mitigate the impact.
EEM is also a generic event framework which has multiple event detectors (not just for GOLD). You can use EEM to watch for CLI commands to be typed, syslog messages to be generated, IP SLA operations to fail, etc. and take all kinds of corrective and notification actions based on those events.
For more information on GOLD, see http://www.cisco.com/en/US/products/ps7081/products_ios_protocol_group_home.html . For more information on EEM see http://www.cisco.com/go/eem/ .
