Not very long back web designers were limited to using only certain types of fonts while building website. These were called web safe fonts and these were those fonts which are supposed to be in every common man PC or Mac. Obviously these were simple fonts and nothing fancier can be done using them, also not to mention repeated use of same fonts led to similar looking pages that were boring too. At some places one would type a text in fancy font (non web safe) on a clear background in Photoshop and put that image in place of real text. Though this made pages look pretty but the drawback was slow page load, extra bandwidth consumption and no indexing of that fancy text in search engines.
With Google Fonts now you are free to choose from thousands of fancy fonts and yet be sure of being web safe. Google is now providing a wonderful service which is a boon for web designers and CMS theme developers called Google Fonts. On the homepage of Google Fonts you can select your desired fonts and then get the include link and CSS codes. For the fonts to load on your website you need to include a code in head section of your theme and add the CSS code to your theme CSS file. This is pretty straight forward and works well on every browser. After adding the CSS all you need is call the style class wherever needed in your template. Using this service is good for two or three fonts but if you decide to use many heavy fonts on a single web page then it will slow down the website. Google shows how much a particular font will delay your webpage from loading while you choose a font to use on your website. Overall this is a fantastic service from Google and only drawback I see here is the bad layout you get while testing your website on localhost and without internet connection!