Are you referring to those "hoo hoo" shouts in Smash it Up? Because those aren't even singing. He's just basically going "woo hoo". Otherwise, I have no idea which part you're talking about. There's no falsetto anywhere in that video...
Take it up with the person who took all that time to write out the description and painstakingly listed what notes he hits in each clip. Sounds like they know what they are talking about.
Almost every person can "woo hoo" like that. He didn't actually hit a pitch there, it was random. "Sounds like they know what they're talking about" doesn't mean they do. That person called three different things "falsetto", when none of them are (two were screaming/shouting, in normal, connected range... the other was this "woo hoo" thing).
This is falsetto: http://www.youtube.com/watch?v=Hz9lhqxl_gQ
Shouting a "woo" at whatever pitch comes out is something everyone can do and is most certainly not "singing falsetto".
Falsetto basically refers to the origin of the sound in the highest parts of someones register. Everyone's falsetto range is gonna be different, so some guy on youtube isn't going to be able to say "this note is falsetto". screaming/shouting places the origin of the sound in the throat, where a person's falsetto range is going to originate somewhere near/behind the sinuses, maybe just above the roof of your mouth. That being said, Dexter has a tendency to sing through his nose, which is not to be mistaken for singing falsetto. Falsetto reverberates inside your skull, where singing through your nose is felt almost exclusively in your nose. There are a lot of things you can do by toying with the origin of your voice. The key to projecting is by trying to get your voice to reverberate in your chest. If you are screaming, shouting, straining by limiting your voice to the throat or higher, you can hurt yourself if you aren't careful. Live acoustic performances, Dexter may use his falsetto range, but usually he is screaming or growling it instead, especially on the albums. I can't think of a clear example of Dexter singing where it sounds like he is singing falsetto.
Melyssa, this isn't something you can learn to identify on the internet. My suggestion to you is that you try taking a couple voice lessons if you really want to understand the differences, even if you are a terrible singer. That is the only way to learn and realllllly understand it.
I can think of three instances of Dexter using falsetto, but as was said none of them are in that video (funny enough, he got some of the right songs, but the wrong parts). And they're all perfect lessons in distinguishing between Dexter's falsetto and his chest/throat/nose voice, because he switches in a short period of time.
Gone Away (2:26) - All of the "Oooooos" are falsetto, everything else is normal voice.
Fix You (3:08) - Exact same thing.
Me and My Old Lady (3:48) - Actually, same exact thing, haha. I didn't realize that before.
So about 10 seconds worth of falsetto in their whole catalog. For the record, I can't think of anyone who sings mostly in falsetto (never mind, Tiny Tim). It's too weak and thin, wears out your voice faster, and keeps you from sustaining notes for long.
Well, you haven't really. When I refer to 'trained', I mean classically trained, with private lessons and schooling for their entire life, which few rockers fall into this category. You've got training from school choir and such, but that's not quite what I mean.
The only singers I can think of off the top of my head who sing in falsetto a LOT are Justin Timberlake, Pharrell, and D'Angelo. I really don't care for too much falsetto most of the time, though. There are only a few songs done in falsetto that I really like (like this one, and this one).