Google Spreadsheets!

Alrighty, I got an invitation to try out google spreadsheets (you can get it too if you sign up on their page spreadsheet.google.com), and lo and behold! here is an online spread sheet app with a loads of fun! The most striking feature is online-collaboration; ofcourse, an online spreadsheet must dedicate its life to collaboration. I guess thats the best use of this application; I wouldnt use an online-spreadsheet to store my company's financial figures; definitely not; but sure I'd like to collaborate with someone accross the world to get some figures right! and once that is figured out, I can download it as .xls (I wish they supported .sxc the oocalc format too). That wud be the primary use of an online spreadsheet.