Firebug integrates with Firefox to put a wealth of web development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.

Mapstraction is a Javascript mapping abstraction library that supports all major mapping providers, dynamic provider switching, image overlay and base tiles, Point, Line, Polygon, GeoRSS, KML support.

Modernizr is a small JavaScript library that detects the availability of native implementations for next-generation web technologies, i.e. features that stem from the HTML5 and CSS3 specifications.

OpenLayers is a Javascript library that can display map tiles and markers loaded from any source.

Pattern is a Python web mining module with tools for data retrieval (Google + Twitter + Wikipedia API, web spider, HTML DOM parser), text analysis (rule-based shallow parser, WordNet interface, syntactical + semantical n-gram search algorithm, tf-idf + cosine similarity + LSA metrics) and data visualization (graph networks).

VIVO is an open source semantic web application originally developed and implemented at Cornell. When installed and populated with researcher interests, activities, and accomplishments, it enables the discovery of research and scholarship across disciplines at that institution and beyond. VIVO supports browsing and a search function which returns faceted results for rapid retrieval of desired information.