Swell.is - Customizable, API-first ecommerce platform for innovative brands, startups, and agencies.
PiP for Mac - Always on top window preview similar to the popular windows only OnTopReplica
Shopify - Shopify is a powerful ecommerce platform that includes everything you need to create an online store and sell online. Try it free for 14 days.
Helium - Helium lets you accept payments by credit card for anything you want to sell online.
WooCommerce - A freely available eCommerce plugin that enables shop facilities on your WordPress website. Functionality enabling extensions & beautiful themes available.
X-Mouse Button Control - XMouse Button Control (XMBC) allows you to create application and window specific profiles.