For those of you who don’t blog, a theme is the basic structure of your blog’s design. While some things are easily customizable, major changes can’t be made unless you’re very html savvy. A theme basically does all the work for you so you don’t have to hire a web designer to build your blog from scratch.
UPDATE 5/21/2015:
After a year of Catch Kathmandu, I finally decided to redesign my blog using a new, premium theme. I chose the Crescent theme through Mojo Themes, a really well-respected platform. I love how many customizable options there are, as well as the clean and elegant design. I was beginning to get a bit frustrated with the limitations of a free theme. For example, I was stuck with the ugly dark blue color, and my self-made “about me” widget was pretty horrific.
With the help of a graphic designer friend, I’ve completely redesigned my blog (again) and I’m really happy with how it looks now! I got a great deal on my new theme through Bluehost, which offered 12 different themes for $30 USD (as in, you pay $30 and they give you 12 themes you can keep forever). Just the Crescent theme itself is $45 USD! Bluehost constantly has great deals like this, which is why I (still) love them so much! For a poor student like me these sales are gold.