greasemonkey is one really cool firefox extension i came across. From the homepage....
"Greasemonkey is a Firefox extension which lets you to add bits of DHTML ("user scripts") to any web page to change its behavior. In much the same way that user CSS lets you take control of a web page's style, user scripts let you easily control any aspect of a web page's design or interaction."
There are a whole bunch of user scripts for general and specific sites as well. An example of a generic script is Linkify. This script turn all URLs on a page into hyperlinks. Suppose a page contains text like http://java.sun.com, the Linkify script would automatically convert it to a hyperlink ( http://java.sun.com ). Google Butler is an example of a site specific user script. From their web-site
"WHAT DOES IT DO?
1* removes ads on most Google pages
2* fixes fonts on most Google pages
3* Google web search:
3.1o adds links to other search sites ("Try your search on...")
3.2o in news results, adds links to other news sites
3.3o in movie results, adds links to other movie sites
3.4o in weather results, adds links to other weather sites
3.5o in product results, adds links to other product sites
blah blah.. go see the site"
Try it out.. May improve usability of your favourite site!!
greasemonkey works by changing the DOM structure of the webpage. Dunno more details..
Does Opera have a good extension mechanism?
IE7 will be released soon I suppose, but firefox really has some really neat features.. and extensions. You think IE7 will stop firefox from taking the market??