How websites are built is directly influenced by limitations of HTTP. Browsers limit the number of simultaneous connections per hostname. HTTP 1.1 specifies 2 p

How websites are built is directly influenced by limitations of HTTP. Browsers limit the number of simultaneous connections per hostname. HTTP 1.1 specifies 2 per hostname, but most browsers allow for 6, some more, some less[1]. So if you are server a bunch of assets at once, you want to spread it across multiple host names (usually edge servers of some sort), so you can get more total, simultaneous connections. HTTP/2 specifically allows for all assets to come from one host. HTTP/2 also has better negotiation on the number of connections allowed and their direction. These changes will see widespread use once CDNs start to take advantage of it. If you are serving a big enough website to take advantage of HTTP/2, you are using edge servers. [1] http://www.browserscope.org/?category=network&v=top http://www.browserscope.org/?category=network&v=top