Acquia has a famous founder and is the go-to company for millions of web sites.
Location: Burlington, MA
What it does: The support and hosting arm for companies using Drupal. Drupal is a popular free, open source content management systems used to build websites.
Funding: $38.5 million
Why it's hot: Drupal was written by Dries Buytaert when he was college and it organically grew into a massively popular CMS today.