Fanboy

[Little_Girl]

A passionate fan of various elements of geek culture (e.g. sci-fi, comics, Star Wars, video games, anime, hobbits, [Magic: the Gathering], etc.), but who lets his passion override social graces.

[Mark Zuckerberg]

1. A person who is completely loyal to a game or company reguardless of if they suck or not.
2. A pathetic insult often used by fanboys themselves to try and put down people who dont like whatever it is they like.
3. See [fool] or [SEGA].

[Little_Girl]

Someone far beyond a simple fan.
No, not the tye of fan which keeps people cool.
An arrogant person who goes into an outburst every time something he likes is questioned. Fanboys usually acuse others of being fanboys. Usually use [1337] and swarm MMORPGs. Fanboys caused alot of fallouts between people when they started arguing about consoles. If you insult something that a fanboy likes, he will spam your computer up and try to insult something that you like. Most words a fanboy uses are in [1337] or end with X0RZ and they spell the work the as teh because they think that it is teh ro><0|2Z!!!
e.g. Counterstrike is teh rockxorz!
Fanboys usually use the word own3d if they beat someone.
Another annoying feature of a fanboy is that if he is loyal to a console, he usually goes to rival console forums and spams the place up with inults about how his console is better.
They take the console war very seriously, as if its a real war.
(Although Im a Nintendo fan, I hate Nintendo fanboys who cant shut up because a Sony fan said that Nintendo is for kids. Dude, chill out, the console war isnt a real war!)

[Rihanna]

An extreme fan or follower of a particular medium or concept, whether it be sports, television, film directors, video games (the most common usage), etc.
Known for a complete lack of objectivity in relation to their preferred focus. Usually argue with circular logic that they refuse to acknowledge. Arguments or debates with such are usually futile. Every flaw is spun into semi-virtues and everything else, blown to comedic, complimentary proportions.
Known for using the phrase
Object of affection = Best Ever
However, while people only really say that as hyperbole, fanboys truly believe it.
Troll the internet to spread the gospel.
Insult/chastise others for using public forums to express an objective opinion, no matter how constructive or, respectful it may be. (Go ahead and admit that its a good game/movie/etc. This fact and anything else will be promptly ignored in favor of cherry picking the negative, and beating you over the head with it.
Tend to resort to petty annoyance replies when backed against the wall. Usually grammar attacks and non-replies.

[Little_Girl]

(n) Technocratic zealots; evangelicals of geekery. Characterized by irrational advocacy of a particular OS, console, company, or franchise.

[Little_Girl]

Well, in the case of Urban Dictionary, its someone whos only posted one definition, and that definition always bashes some other system.

[Justin Bieber]

a boy or young man who is a fan of someone or something such as an actor, a type of music, a piece of technology, etc.:

[Donald Trump]

A male fan, especially one who is obsessive about comics, music, movies, or science fiction.