HubSpot is on a mission to replace the world’s annoying, interruptive marketing with marketing that people love. HubSpot software is the most powerful, tightly integrated and comprehensive marketing software available, putting personalized inbound marketing into the hands of any business. Over 13,000 companies in 70 countries use our software to create lovable inbound marketing to attract, nurture and convert leads into an accelerating stream of new customers and revenue. HubSpot has been named one of the most promising, fastest growing companies by Inc, Forbes and Deloitte for the best possible reason: customer results. HubSpot has 800 employees, was founded in 2006 and is based in Cambridge, MA.
I think this slideshare from HubSpot pretty well sums it up:
Learn more about What is inbound marketing via the official page on HubSpot.com