50 Companies That May Be the Next Start-Up Unicorns

Mixpanel  - What it does: Mobile analytics

Optimizely - What it does: Technology to optimize websites

Squarespace - What it does: Online marketing tools

Taboola - What it does: Online marketing

http://bits.blogs.nytimes.com/2015/08/23/here-are-the-companies-that-may-be-the-next-50-start-up-unicorns/?ref=technology&_r=0