WordPress is one very useful and popular content management system. As with any CMS, there is also a bunch of themes you can use to have a unique looking site.
The problem with WordPress though is that with it being free and open source, anyone can create a theme for it - that includes hackers. So when choosing a theme for your site you must be sure you get it from a reliable source. If you install a theme made by a hackers, they can easily get hold of very important info from your site, use your server resources or can completely destroy your site.
The most reliable place you can get a theme from is WordPress' very own themes site. WordPress have a dedicated site for approved and safe themes that work perfectly with WordPress. These themes can also be customised in many different ways and can include functionality you wouldn't usually see in other themes.
The WordPress themes site has an array of themes which cover lots of different topics. You can have a photography theme or a very minimalistic simple looking blog.
We'll soon be launching our own line of premium WordPress themes so make sure to keep an eye out for them.