I don't exactly understand how to use grids (or even why). Is it for visual consistency or is there an underlying usability/maintainability benefit to using grids?
http://www.markboulton.co.uk/journal/comments/five-simple-st...
http://www.subtraction.com/2004/12/31/grid-computi
How to use grids? It is usually as simple as adding some css, divs and classes. At its most basic, you can use a gridpaper background or this javascript gridder: http://gridder.andreehansson.se/ that works well with the http://960.gs grid framework.
Why I use grids?
- maintainability and cooperation
- visual consistency across browsers
- less development time spent with display bugs
Why I don't use grids?
- Can become a bit boring/holding you back
- Not all designs work with even columns (for example those based on the golden ratio)
- Code bloat (you are using divs like columns and rows, in almost the same way one would layout a page with tables, also devs sometimes forget to remove the unused classes from the production CSS)
I prefer using the semantic approach to writing CSS using mixins (both Compass and LessCSS have mixin support). That keeps the html markup clean and maintainable.
Also to note, LessCSS (used in Bootstrap) is different from Less Framework (http://lessframework.com/), which is a CSS grid framework.
It's primarily used as an aid for visual layouts, but it took on the other useful qualities everyone else has listed as the grid frameworks got popular in the web.