hubspotHubSpot, a startup that bills itself as a one-stop shop for online marketing campaigns, has closed a $16 million third round of funding — a high sum for a company in that space.

Based in Cambridge, Mass., the company competes with the likes of Coremetrics (another well-funded firm), which also combines analytics and marketing tools to allow clients to optimize their advertising strategies.

The funding was led by Scale Venture Partners. Rob Theis, managing director with Scale, will join HubSpot’s board of directors. Existing investors General Catalyst Partners and Matrix Partners, who led the $12M A round in May 2008, also re-invested in this round.

hubspot-screen-shot-traffic-events-leads-1HubSpot’s gimmick is what it calls “inbound marketing” rather than outbound marketing (*). Inbound marketing advocates going after customers who’ve already expressed an interest in your brand or products via a Web search or other action.

It also distinguishes itself by offering a free search engine optimization product called the Website Grader, which tells you roughly how good your SEO tactics are. For example, VentureBeat has better SEO than 90 percent of the sites HubSpot has graded. All of these tools are designed so that client companies don’t have to hire a pricey third-party firm to architect and deploy what might otherwise be a simple marketing plan.

(*) Many people who work in marketing use the term inbound marketing to mean, more or less, product management.