If you want to get your site loaded for your readers as fast as possible, yoast.com has a great article about using a CDN with WordPress (though any site can benefit from it).
The article includes a bunch of information about CDN’s (including the definition you’re about to read, so don’t worry if you’re lost), and why you should probably be using one if you don’t hate your readers.
Here’s a tidbit from the post to get you started…
CDN stands for Content Delivery Network or Content Distribution Network. Basically, it’s a bunch of highly optimized servers all across the world, with a bit of unique logic worked into them: you’ll always hit the server that’s closest to you. This leads to huge performance improvements for sites that have visitors from all across the world, like this one.
My images were coming from the US, which was better for like 50% of my readers but pretty slow for a lot of my European readers (about 35% of my readers are European). Now, for them, these images can come from the CDNs servers in London, Amsterdam or Frankfurt, whichever is closest to them.
If you’ve got readers from all over the place, a CDN is likely a very good idea if you can afford it (it’s surprisingly affordable usually). Yoast.com is claiming a 3x (or more) increase in load speeds for most readers, and that adds up pretty fast if the site gets a lot of traffic.
Definitely something that every budding blogger should look into.