What the heck is Ultrapixel?

Yes I'm still talking about HTC One.
You wont find any S4 story or some sort here.=P

For those who was wondering why the HTC One only have 4MP camera and didn't quite understand the purpose of Ultrapixel, and was browsing the spec and say,
''whatt? only 4MP?? nahh..I'm going for other phone." 
hold your horses peeps, here's a good read,

HTC One and Megapixel myth 

First you have to be familiar with Samsung Galaxy S3 8MP camera and Nokia 808 Pureview 41MP camera.
Well not necessarily actually. U'll know when you read this.=P

So to make it simple,

I quote this from the article,

“Light is basically a bunch of photons in wave form. The bigger your pixel is, the more of that you can capture,” Whitehorn explains. “If you think of it as a bucket, it’s going to take in more rainwater than a tiny cup. You can put a lot of little cups to try and collect the same amount of light in the same space. What happens is you have equal amount of light, but also you have the space in between the cups, which is called the noise.”

The comment sections give all kind of positive and negative perspective. but this particular comment sums the why part,

rmonster  Stephen Drake • a month ago

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You know what the megapixel rating on the Nikon D3s is? 12.1. 12.1 on a pro-level DSLR. Even 8 seems a bit ridiculous in comparison for a device with such a small lens and aperture. 12MP images aren't even useful right away; you either shrink or crop them so you can display them. Camera phones need to have fewer, but more sensitive and larger pixels to make up for the tiny aperture and minimal lens capability. This is actually a huge step in a good direction. Props to HTC to make a go of it.

P/s: The comment section is hilarious too. So grab a popcorn and enjoy ;)