1) well said
2) said in a agreement or as an affirmative response to a question
3) can be used as a greeting.
( for 1 and 2 also see "I heard that." and "Amen" and "Yes")
Disambiguation - Also a popular bloated word processing software product from a Redmond, WA based software marketing company.
Rep. Nancy Pelosi (D) San Francisco - also seems to have indicated that this expression puts her in some sort of trance.
( origins unknown, but seems like it is street slang from an ebonics dialect. Some say it comes from hip-hop culture.)
2.) You goin' to that rave tanite* ? response ....word
3) (used upon encounter with someone - usually a bro' or dawg or homey, sometimes a bud ) - word up - also see - 'sup, what up and what's up
*tanite - see tonight and tonite and 2nite