Private equity investor Accel led a $200m Series C round in Klaviyo, a customer data and marketing platform for online businesses, with participation from existing investor Summit Partners. "Klaviyo helps online businesses of any size break out of the one-email-fits-all marketing mentality, because blanket communications aren’t effective for anyone. Every online customer has unique preferences that influence how and where they make purchases and we’re able to help sellers leverage their own customer data to create an experience they control -- one that is ultimately measured in revenues generated, not pages viewed," Andrew Bialecki, Klaviyo Co-Founder and CEO.