CloudFlare, a security startup that has its roots in open source spam protection network Project Honey Pot, just raised $20 million in a Series B funding round, led by New Enterprise Associates. Existing investors Pelion Venture Partners and Venrock Associates also participated in the round.  CloudFlare will be using the capital to increase its staff and expand capacity – it currently powers about seven billion page views a month and leverages 12 datacenters.

 “$20 million is definitely a lot of money — but effective security tools have the potential to be hugely lucrative in the months and years ahead,” the company notes in a statement. “As more people come online, website security will almost certainly become an increasingly important issue.”

CloudFlare‘s success lies in the fact that it’s a freemium product, which can be installed on a website just by changing its domain’s DNS settings.  This helps accelerate websites while also blocking DDoS and malware attacks. This approach made CloudFlare a pretty popular service; so much so that according to the company, it has served over ten percent of global internet users in the past 30 days.

CloudFlare has a free version, a premium version with more options that costs $20/month, and an enterprise version currently under development. One of the most notable users of the service was hacker group LulzSec. Its website, which it used to post links to all the sensitive data it managed to obtain, was shielded by CloudFlare from attacks by other hackers.

Cloud security is a major topic, driving a lot of demand to offerings such as CloudFlare. There will always be gaps to fill in though, and one of the concerns that’s been raised recently is the government’s subpoena power over personal or encrypted information, and a recent case that may act as a precedent for forcing individuals to decrypt personal data.