Amazon S3 or Amazon Simple Storage Service is a service offered by Amazon Web Services (AWS) that provides object storage through a web service interface.
Fly is a platform for running full stack apps and databases.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.
Typekit is an online service which offers a subscription library of fonts.