user_info is a class to retrieve information about the browser the user is using to access the current site script. It can analyze the user agent string sent by the browser in the current HTTP request and extracts the type of browser, user machine operating system, user machine IP address, accepted character set encoding, language name, and whether the user is a spider/bot.
jBoom is a program for remote storage and management of browser bookmarks and mail addresses. It allows accessing a central set of bookmarks and addresse from any system connected to the Internet. It is browser, mailer, and system independent, not bound to a dedicated server, and doesn't require a special Web service. The bookmarks are kept in an XML file on the remote system. A local copy can be stored on the client. The program may be started from the client or over the Internet from an HTTP server. Entries can be activated from the main window or the system tray.
Firekeeper is an intrusion detection and prevention system for Firefox. It is able to detect, block and warn the user about malicious sites. Firekeeper uses flexible rules similar to Snort ones to describe browser-based attack attempts. Rules can also be used to effectively filter different kinds of unwanted content.
RLC is a tool that performs reciprocal link checking automatically. Simply tell it where the remote Web pages you wish to monitor are, and the URLs of your links. It will then crawl the remote Web pages and give you feedback on the latest status (found, link not found, or page not found/network error). You may activate the checking as needed, or set up cron to carry out the checking once a week or so.