Mailmatch is a newly announced service that enhances email marketing lists by providing social data. Users can upload their email lists either by pasting emails directly or through a Mailchimp integration. The service gathers publicly available social information, such as Facebook handles and Twitter followers, to enrich the data. Additionally, Mailmatch offers a downloadable CSV file with expanded attributes, including social profiles, company information, and job titles, all powered by Clearbit's APIs. For ongoing email list processing, integration with Clearbit's APIs is recommended.