Web (HTML/CSS/JavaScript/DOM)
http://www.howtocreate.co.uk/
Excellent site with lots of good tutorials about HTML, CSS, JavaScript and DOM. The author always try to make things cross-browser and standard compliant.
http://www.brainjar.com/
Nice site with nice DOM tutorials and already made scripts. However, some scripts are not really cross-browser. DOM tutorials are nice to beginners, though.
http://www.w3.org/QA/2005/04/php-session
Why using PHP sessions causes invalid HTML and XHTML to be generated, and how to fix it.
http://dean.edwards.name/IE7/
IE7 is a JavaScript library to make IE behave like a standards-compliant browser. It fixes many CSS issues and makes transparent PNG work correctly under IE5 and IE6.
http://www.hixie.ch/advocacy/xhtml
An excellent text that says you must not use XHTML if you do not understand it.
http://docs.sun.com/source/816-6408-10/
Old documentation of JavaScript 1.3, previously available at Netscape site.
Opera-related
http://denilsonsa.selfip.org/~denilson/opera/
keyboard/; menu/; mime.css (for Opera 7); mouse/; toolbar/; userjs/
http://denilsonsa.selfip.org/~denilson/txt/MyOperaWishList.txt
It is somewhat outdated, but some wishes are still valid.
http://www.howtocreate.co.uk/operaStuff/operaObject.html
Description of "window.opera" object.
http://www.howtocreate.co.uk/operaStyles/
Some CSS files to change the look of Opera IRC. I use "XP Style I".
http://xml.opera.com/update/
Opera gets this URL to know what is the latest version available. The server sends different data depending on User Agent (in other words, you must send a valid Opera UA).
http://xml.opera.com/spoof/
Opera uses data from this page to automatically spoof User Agent on some sites.
Useful topics to not forget
http://forums.gentoo.org/viewtopic-t-457432.html
Talking about gnupg 1.9.20 and 1.4, and why both must be installed at same time. We must remember to uninstall old version as soon as it is not needed anymore (when a new version comes out).
Programming contests
http://acmicpc-live-archive.uva.es/nuevoportal/
Thousands of problems with online judge.
Other
http://diveintomark.org/archives/2003/08/04/xp
A very nice description of how he could install Windows XP in 147 steps.
http://my.opera.com/WildEnte/blog/show.dml/78214
An analogy for Browser Wars
http://www.youtube.com/watch?v=HUcgXYGe_WQ
Yuzo Koshiro, game music composer, the genius behind "Streets of Rage" scores, plays DJ in a Japanese Club.
http://rapidshare.de/files/12655677/yuzo.avi.html
Downloadable version of above video. (98MB)
http://usbirboy.sourceforge.net/
I want to make one of these, someday. :)
http://video.google.com/videoplay?docid=3163263343187879320
A video with lots of "incredible machines". Very interesting. Makes me want to construct one of those. :)
http://www.guimp.com/
Smaller than a small fingernail, the world's smallest website measures only 18 by 18 pixels yet is packed full of fun projects including pong, pacman, space invaders, pinball, a blog and pixel art. Fortunately, Opera has zoom!
My other pages
http://denilsonsa.selfip.org/~denilson/
My "official" page (alternate address).