>What's the win going from 16 to 12 columns?

Was wondering that too. First thing that comes to mind is that 12 columnn is more flexible for responsive layouts, which is another big addition in v2.

For example, since 12 is divisible by 3, it's easier to create a responsive site with 3 vertical sections that collapse into a single vertical section on mobile devices. (Like the Less Framework's mobile layout: http://lessframework.com/. Not the best example, I know I've seen a better one, but can't find it atm, but that gives the general idea.).

Don't know for sure if that's the reason, though.

A 12-column grid lets you easily mix 3-colum and 4-column layouts. A 16-column grid does not.

[edit] Essentially it's more expressive. Another commenter correctly mentioned that it could have the same advantages above for a responsive design. 12-columns allow for greater freedom of expression at all display sizes.

You get better divider flexibility with the columns.

You basically can divide it in half (6 columns each), in thirds (four columns each) in fourth (three columns each), in 6th (two columns each and in all 12 plus of course spanning the entirety.

16 gives you only 1, half,

Any recommendations on how to use grids? I've seen them talked about but I don't actually know what to do with it. How does it help you?

You use grids to group and align your content.

Basically you need look at your design in order to determine what would make most sense.

A very popular choice is to divide it into three equal sizes and then have one of them be the right or left column, while the two others combine to form the other column.

So you end up with two columns one for content and one for navigation (typical blog look)

Grids can obviously also be much more complicated as those used in photoshop, 3dmax, word or windows/osx.

If you want to get really into grids I can recommend probably the best book written about them.

Josef Muller Brockman Grid Systems

http://www.amazon.com/Systems-Graphic-Systeme-Visuele-Gestal...

I have this book and like it, but I doubt it's particularly useful for the typical nerd wiring up a credible looking web application.

Can you recommend a different book that would be more useful to someone trying to edit Twitter Bootstrap from a beginner's perspective?

You don't need a book. You just need to build a hello-world application with the Bootstrap CSS/JS code, using one of the layouts they provide as a starting point. Then just use the page of Bootstrap demos as an a la carte menu as you find yourself needing UI features.

The Grid Systems book that was recommended earlier is a better bet if you're a typographer or graphic designer, and particularly if you're thinking about designing novel grid systems. But you're not doing that. The Bootstrap grid is trivial and does not require any background in design to use.

That doesn't mean one can't educate oneself on what it is though no?

I mean I am a designer but still taught myself programming and is generally interested in technology.

Understanding design better will make you a better programmer IMHO.

All I can offer here is my opinion. I have the book. I like it, because I geek out a little on typography and graphic design (I am horrible at both). I wouldn't put the book on my "buy immediately" list of practical design books for developers.

_Elements of Typography_ (which also has some coverage of grids, along with meter systems), yes. _Elements_ is a buy-immediately book (and a joy to read).

Khoi Vinh's Ordering Disorder is a good book on grids, and its focused entirely on web design.

Although, nothing beats Brockmann's Grid Systems book mentioned earlier.

http://www.amazon.com/Ordering-Disorder-Principles-Design-Vo...

Your whole web app becomes a giant nesting table, using divs, classes, and CSS instead of HTML table markup. The math on cell sizes is already done for you, and you're not stuck with wonky table markup and styling.

You can line up every element in your design without figuring out and writing widths and margins for every element by hand. You just assign one of the provided class names and you automatically get the desired result.

So how do you find what to adjust in the CSS? Just read through it until you figure it out? For example, if I wanted to make four columns instead of three?

You don't have to edit the CSS at all. You don't even have to open the file, ever, to use Bootstrap. Just link it in the head of your document like any stylesheet and use the class names from the documentation.

Want something on your page to be 3 columns wide? <div class="span3">...</div>

Want to make it 4 columns wide instead? <div class="span4">...</div>

You sirs, are both awesome. I think I need to do more research into all of this and find a good how-to guide because if I didn't know how to do the above, I probably shouldn't be doing it until I know more. I've been down that path before and it leads only to frustration when I realize I know no idea what I'm doing :)

In Haml:

  .span3
    = render :partial => "col1"
  .span3
    = render :partial => "col2"
  .span3
    = render :partial => "col3"
  .span3
    = render :partial => "col4"

Or, to do 3-col:

  .span4
    = render :partial => "col1"
  .span4
    = render :partial => "col2"
  .span4
    = render :partial => "col3"

Nothing in the partial needs to especially care about the grid (as long as its simple) --- but if it wanted to, it could nest columns.

or better yet, you have semantically named elements and assign them column values in your .less file:

    #sidebar {
      .makeColumn(4);
    }
    #main_pane {
      .makeColumn(8);
    }

    #sidebar
      = render :partial => 'common/sidebar'
    #main_pane
      = yield

Wondering the same. Sorry, didn't mean to imply it's a win. For me, I'm going to have to adjust a ton of layout. It's probably not all that bad if you've got a decent template structure, though.

It's a headache, but as I was saying, it's so much quicker to work with than many of the others that I might just dedicate some time to do the work and get on board.

You can also change the number of columns using LESS.