Christopher Finke created a Slashdot extension for Firefox, the extension allow to :
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* A “Reply to Selected Text” option is added to the context menu whenever you select text in a Slashdot comment or topic. The reply box is then pre-filled with the selected text, and can be formatted using your choice of format string. The default is ‘<blockquote>%s</blockquote>’.
* A link is added at the end of each comment (next to the “Reply to This” link) that allows you to toggle open/closed all of that comment’s replies.
* Links to the Coral Cache, Mirrordot cache, and Google Cache are added after each link in a article description.
* The new tagging sections under each article description can be hidden if desired.
* You can choose to have all Slashdot pages styled like one of Slashdot’s sections. For example, if you’re a fan of the Games section’s hideous purple and black color scheme, you can have every Slashdot page look just as horrifying!
* For the links in the comment section labeled “X Replies below your threshold,” there is an option to have those comments load in the current page when you click the link rather than loading a new page. The newly loaded comments will have a pale yellow background to differentiate them once they have loaded.
* Have the “Parent” link at the end of each comment link to the parent comment on the current page rather than a new page.
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It have been Slashdotted too :

I’ve been working on Slashdotter Firefox extension for Slashdot users, and version 1.2 has been approved by the Mozilla admins. Features include the ability to auto-add cache links after story links (from any of Coral Cache, Google Cache, or Mirrordot), a quick-reply feature that adds a ‘Reply’ option to the right-click menu when you select text in a comment, the option of styling all of Slashdot’s pages like a chosen Slashdot section, links in the comment sections that allow you to toggle open/closed all of a comments replies, and more. All of Slashdotter’s features are optional, and the extension is compatible with Firefox, the Mozilla Suite, Seamonkey, and Flock