these themes are 2-3 columns and have a sidebar with a pic. used for fashion, interior design, etc..
these themes have multiple columns and usually 2 sidebars, one for a picture/desc and the other for links. Great for colorful posts
these themes are usually 2 columns with a sidebar. the posts are long lengthwise
or modern. clean-cut and intelligent look; usually there's a lot of thin borders and simple fonts
these themes can be any amount of columns, with or without a sidebar. they're unique
these are the best kinds. lots of fun colors/borders and awesome fonts. there's always some kind of cool transition/hover effects
or beachy / summer; these themes are for colorful, summery posts and usually have multiple columns with simple sidebars and features.
the use for these themes is just to have a place to list multiple URL's for a certain group