How firefox3.5 will be useful for web developers?

Firefox3.5 is 10 times faster than firefox2 versions. A good news from mozilla, that firefox3.5 have many new features for web site and application developers.

HTML 5
Using audio and video in Firefox. In the older version of firefox, you need to download a plugin for flash to view the videos in Youtube. But using firfox3.5 and HTML5 you can view the videos without any plugins installed. And also they are very faster than ever.

Offline resources in Firefox
Firefox 3.5 now fully supports the HTML 5 offline resource specification.


Drag and drop
The HTML 5 drag and drop API allows support for dragging and dropping items within and between web sites. This also provides a simpler API for use by extensions and Mozilla-based applications.

Newly-supported CSS features
The :before and :after pseudo-elements have been updated to full CSS 2.1 support, adding support for the position, float, list-style-*, and some display properties.

opacity
The -moz-opacity Mozilla extension to CSS has been removed in favor of the standard opacity property.

text-shadow
The text-shadow property, which allows web content to specify shadow effects to apply to text and text decorations, is now supported. Also..
-moz-box-shadow, -moz-border-image, -moz-column-rule, -moz-column-rule-width, -moz-column-rule-style, -moz-column-rule-color added newly.

Shadow effects in a canvas
Canvas shadow effects are now supported.

Applying SVG effects to HTML content
You can now apply SVG effects to HTML and XHTML content; this article describes how.

And many more....

But the hope is that ie8 should support HTML5 and css3 with out any bugs. Coz a report says that majority of the people are using ie6 still. for more information on HTML5, please read HTML5