In the late 1990's-Early 2000's, this internet slang term's meaning was literally 'laugh out loud', and was used to express the laughter of the user of the term. In these times, the term was used appropriately and was not over-used.
Nowadays, the term is overused to the point that people loathe the usage of the term. It is now used to simply attempt to advance the conversation, but often instead kills the conversation. The term is also used when the person is not paying any attention to the conversation, and has nothing relevant to say. The person will then reply with 'lol', and the conversation will be effectively ended. The slang terms 'XD', 'hahaha' and such are occasionally used instead.
The term is also often used by the younger generation in actual real-life conversations, which has the same meaning as its new meaning.
Nowadays, the term is overused to the point that people loathe the usage of the term. It is now used to simply attempt to advance the conversation, but often instead kills the conversation. The term is also used when the person is not paying any attention to the conversation, and has nothing relevant to say. The person will then reply with 'lol', and the conversation will be effectively ended. The slang terms 'XD', 'hahaha' and such are occasionally used instead.
The term is also often used by the younger generation in actual real-life conversations, which has the same meaning as its new meaning.
Original example:
Person 1: I just finished watching <funny movie name>, and <name> said <funny line>.
Person 2: Lol! (Person 2 is genuinely laughing at Person 1's statement).
New Internet meaning:
Person 1: I was walking down the street today, and someone blew smoke in my face.
(Five minute wait)
Person 2: Lol (Person 2 is using the term as a way to attempt to advance the conversation, which has now been killed by Person 2's statement).
Real-life conversation usage: Same as meaning 2
Person 1: I just finished watching <funny movie name>, and <name> said <funny line>.
Person 2: Lol! (Person 2 is genuinely laughing at Person 1's statement).
New Internet meaning:
Person 1: I was walking down the street today, and someone blew smoke in my face.
(Five minute wait)
Person 2: Lol (Person 2 is using the term as a way to attempt to advance the conversation, which has now been killed by Person 2's statement).
Real-life conversation usage: Same as meaning 2
by Meee657 December 30, 2011
Get the lolmug. by Nick7805 December 15, 2012
Get the Lolmug. 
LOL is an acronym for Lucifer our Lord. Be careful when using it around your Christian friends, they might think you are the devils spawn and burn you at the stake. Or possibly think you are laughing... Either way, it's a good way to tell who your fellow Lucifer Lovers are and build the most evilist cult in the world.
by NastyDelicious May 27, 2014
Get the LOLmug. by maharmanlarmamamama January 31, 2008
Get the lolmug. by asslikethatttt July 7, 2007
Get the lolmug.