A WordPress theme is a file that holds the looks and feel of a WordPress blog. Each theme is having a group of layouts. The layouts are simply the structure of a page in the theme.
There are many types of layouts and these are listed in this article for your understanding. The layouts listed below are not the only layouts available, there are many more. Only the important ones are being listed here for your understanding.
Single column layouts are a simple single column of text which runs down the entire page. This layout does not have any sidebar and this is a setback for lists, popular posts, etc. Since this layout does not support utilities for a blog, it is not that popular.
This is a layout that was used in the bygone era and the same can be used if you require a minimalist design for your blog.
Two Column Layout:
As the name suggests these are layouts that have two columns, one predominantly used for the main content text and the other column used as a sidebar. The sidebar can be for feeds, ads, and other highlighted information.
This is popular to an extent among the webmasters since it provides room to publish additional information apart from the content of the website.
Three Column Layout:
The three column layout is the most popular layout among the bloggers. This resembles the 3 column looks of newspapers and magazines(tabloids). This layout can have the columns anyways, there can be three equally wide columns or a wide column for content and two sidebars.
Even the sidebars can be placed both on the right or the left and the other way would be to have a sidebar each in both sides of the content.
Four Column Layout:
This is another rare layout which can have four evenly spaced columns or two wider columns for content and two leaner columns as sidebars.
This layout isn’t that popular for a simple fact that the website looks cramped with data and the reading becomes tougher.
Photoblog or Gallery Layout:
Popular among photographers and designers alike, this layout is specifically designed to showcase the works of designers. This is full of images which can be pictures of photographers or logos and webdesigns by the designers.
There can be no text or very little text in content. These content are typically contained in thumbnails and would give the visitor the full view of the work once the thumbnail is clicked.
These are not the only types of layouts as mentioned earlier. There are many more layouts available on the net for free. The other types of layouts just to list them are, five column layout, ecommerce layout, classifieds layouts, magazine style layouts, etc.,
The number of columns on a layout and the type of layout should be well chosen based on the niche of your blog. The better the look and feel of your blog the better the retention of visitors.