HarrR!

(1) Conversation opener.
(2) Greeting.
(3) Said randomly when drunk, or any other time.
(4) Said in order to keep yourself hard. (www.funwithsex.org)
(5) Commonly used between friends, more of an inside joke thing.
(6) Pirate thing.
(7) Often a few different spellings and or capitalizations with the same meaning.