Hi,
Cloudflare for those who have not heard of it, is a free CDN.
Using Cloudflare you benefit from a faster website, security protection etc.
https://www.cloudflare.com/overview.html
They have a WordPress plugin as well:
http://wordpress.org/extend/plugins/cloudflare/
I have Cloudflare on a number of standalone WordPress sites and it works great. I have not used it on a multisite yet. Anyone using it? This is a good place to share tips.