Description: MathJax is an open source JavaScript display engine for mathematics that works in all browsers. It allows you to include math equations and formulas on your website that will render beautifully cross-browser.
Type: software
Pricing: Open Source
Description: Reddit is a social news aggregation, web content rating, and discussion website. Registered members submit content to the site such as links, text posts, images, and videos which are then voted up or down by other members.
Type: software
Pricing: Free