In a pop culture sense, "goon," has been used in many popular songs by artists who are quite famous.
Rapper Brisco, among others, uses the term to describe himself and his friends from a particular region of Miami in his song featuring Lil' Wayne "I'm in tha Hood": "Opa-Locka Goons!"
Thus we see the definition of "goon" being applied in a geographic sense, identifying a group of people from a certain region with a set of shared characteristics or habits.
"Goon," primarily through the lyrics of rapper Plies, has begun to take on a similar, but new meaning to Brisco's usage. Plies is a rapper notorious for being the tough guy on the block, the "G" who has never snitched, and is going home to his "Bust it Baby" in one piece or in a casket. Plies persistent use of the word to describe his large group of thugs has caught on in a humorous sense with rap-listeners and non-listeners alike.
With the advent of the word being used in a such a serious manner, it has grown to describe a variety of people and individual characteristics.
A goon can be a thug - someone who you know at any given time could rob a conveinence store for you.
Ex: "That kid's a goon - I wouldn't mess with his girl bro."
A goon can be someone who acts goofy, strange, or simply humorously during inappropriate times.
Ex: "We brought over a girl for him to spit game at - but he was a goon and played beer pong all night instead."
A goon can also be someone or something that is mischievous, clever, or crafty.
"I've got a date on Wednesday, Thursday, and Friday; the girls are all friends, but none of them know...I'm a goon if I pull it off."
A situation where many goons are present in a contained space, or an event run by many goons, would be referred to as "goonville," or "Goon Squad."
Ex: "Look at this "goon squad," let's get outta here.
The step above a goon (which of course is all relative to how much of a goon "person A" is) would be a "Goblin."
All the goons around me so you know I'm comin'
Half a brick in my pocket ten stacks on me!
And by lil wayne in "A mille" when he says, "I go by them goon rules: if you can't beat'm then you drop'm". FYI Plies, lil wayne, bird man, and gucci man are all Bloods (see lil wayne's verse in shory lo's "they know" remix when he says, "Su-Wu gang, and if you aint wit it then you in the food chain.." (su-wu is a term for blood gang members).
Goons have neckbeards, no real-life social skills, a tendency for whining about dumb superficial crap, and a knack for shutting down anyone who has anything worth making fun of. They're known for their sarcastic and elitist tendencies, though many on the internet find them hilarious.
Usually proud members of such Forums as GBS, BYOB, FYAD, or ADTRW, goons patrol the Awful Forums attempting to type funny jokes while their fingers slip off the keyboard due to Cheetos grease.
Goons spew overused catchphrases like "Do you have stairs in your house?" or "All your base are belong to us," though they are also responsible for founding and popularizing various internet memes, web sites, and trends.
There are many varieties of goon, depending on the particular forums they frequent at SA. GBS goons are often sarcastic and clever, while FYAD goons are elitist and abstract, BYOB goons are laid-back and random, CC goons are artistic and very critical, and ADTRW goons are anime-obsessed.
Goon2: OMG ur a goon 2?
Goon1: Wow yeah do you have stairs in your base belong to us?
Goons: Why do I have to pay 10bux to get into these forums? If it costs me an entire week's allowance, than I don't want to be a goon.