That only works with apps that use libcurls. and when you add your proxy to /etc/profile guess what would happen. The browser would cease to work. so yeah you might be able to get gpodder and maemo and some few apps to connect to the internet. your broswer would stop working. and to use the browser, you would need to open terminal and use vi to comment out the http_proxy line. reboot the device and then you can use the browser ( which would mean you wont be able to use any other app till you uncomment the http_proxy line and reboot the device again). you also have to do the same thing if you want to use a 3g network or use another wireless connection which doesnt require proxy.,. now if add proxy to /etc/profile fixes all the problem than i would be a happier man but it doesnt. it works with only apps that use libcurls which are much. so you still miss out on internet radio, qik, conversation and all the plugin (twitter,irc,yahoo, msn etc) wikitunes, mastory.
I have used symbian, windows, mac, iphoneOS, LInux (kde and gnome) and maemo has the worst proxy support I have ever seen in an OS. Appalling is an understatement