TouchGraph is a set of interfaces for graph visualization using spring-layout and focus+context techniques. Current applications include a utility for organizing links, a visual Wiki Browser, and a Google Graph Browser which uses the Google API.
Freetag is an easy tagging and folksonomy-enabled plugin for use with MySQL-PHP applications. It allows you to create tags on existing database schemas, and access and manage your tags through a robust API.
Minimalistic but full-featured address book in your web browser.
adx is a standalone and portable web app (online and offline).
Contact Management, portable, small (<200KB), lightweight, contact tagging, geo mapping, web accounts, trigger phone/Skype calls, etc.
... [More] FUNCTIONALITY
vCard (as file or QR code via offline generator), embedded Microformats (hCard 1.0, XFN).
HOW IT WORKS
Your address-book (XML file) is transformed in your web browser (via XSLT) to a full-featured web application (HTML).
Web browser for viewing online or offline (some like Chrome need a small command line parameter for offline viewing); no server, plugin or anything else needed. Any text editor can be used for contact editing (addressbook.xml). [Less]