To be honest, I never really understood grids until I learned it in this class. Grids are important in making sure everything is aligned and balanced. But as we learned a couple weeks ago, there isn't a right or wrong way to use a grid. It's really up to the designer on what looks good. Grids are there as a guideline. It is a tool used to organize content, but the casual viewer will never know or will never really care. Generally, negative space is good and lots of pictures are a good way to go about organizing a spread.
Grids are not just vertically, they can also be used horizontally. But it really depends on the copy.
Examples:
Example I found of "The Helvetica Post" as a way to show grid.
Interesting ways to layout contents
The four most common grids.
Every internet site uses grids.