A family of Microsoft word processing software products for creating web, email, and print documents.
Depending on version of OS X please see either:
http://support.apple.com/kb/PH14361 [10.9.x]
or
http://support.apple.com/kb/PH11463 [10.8.x]
Note that the service can be activated by inadvertently tapping fn twice.
I'll be curious to see what happens for Jim. As I said, I've never turned mine on. Also, I have they keyboard shortcut set to "off" so hitting the fn key would do nothing.