AJAX

[rus] dklab_multiplexor: постоянное Javascript-соединение с сервером в условиях сотен тысяч онлайн-клиентов / Высокая производительность / Хабрахабр

http://habrahabr.ru/blogs/hi/69457/#habracut high-load web notification system or how to do persistent connections in ajax/js. Useful for counters, friend-status updates and so on. Example is given for libevent-based daemon in perl.

Apache2::UploadProgress - Track the progress and give realtime feedback of file uploads - search.cpan.org

http://search.cpan.org/~ceeshek/Apache2-UploadProgress-0.2/lib/Apache2/UploadProgress.pm module that allows u to make upload progress bars

Concurrent Ajax

http://www.hunlock.com/blogs/Concurrent_Ajax notes on how to make concurrent ajax calls

Another 10 web operating systems reviewed

http://franticindustries.com/blog/2007/06/16/another-10-web-operating-systems-reviewed/ web os review