Mailchimp’s email engine was built from the leftover code of a dead e-greeting-card site.
Ben Chestnut and Dan Kurzius were running a web-design agency on dot-com severance when clients asked for email help in 2001. The pair salvaged code from an e-greetings site they had abandoned, and reused a chimp drawn for one of those cards as the logo.
Mailchimp on Brandseum