Lots of older laptops have an aspect ratio of 4:3. This is simply because it was the standard back then (nearly all CRTs are 4:3 aswell) When you're very used to widescreen, this can seem very "squarish" but it's not quite.
Anyways, the new standard is 16:9 but can also be 16:10. Most cinema-made movies have an AR of 21:9! That's why you have big black bars when watching them even on a normal 16:9 widescreen. 21:9 widescreens are become available more and more now aswell.
Yeah, wide screen is the trend of PCs and laptops since around 2006/2007.
You can blame or thank the adoption of HDTV which has an aspect ratio of 16:9 so many people are used to looking at a display with that aspect ratio. 16:10 ratio laptops are rare, I think only MacBooks use that type of screen a long with a few PC laptops.