Boston-based marketing automation firm Klaviyo wants to change the way marketers interact with data, giving them direct access to their data and their customers. It believes that makes it easier to customize the messages and produce better results. Investors apparently agree, awarding the company a $200 million Series C on a hefty $4.15 billion valuation today. The round was led by Accel with help from Summit Partners. It comes on the heels of last year’s $150 million Series B, and brings the total raised to $385.5 million, according the company.