Online collaborative office tools open source

Etherpad is a free, open source, online, collaborative wordprocessor. It is very good for use on lightweight devices like phones, netbooks, tablets and more. Visit https://www.etherpad.org
Etherpad is a free, open source, online, collaborative wordprocessor. It is very good for use on lightweight devices like phones, netbooks, tablets and more. Visit https://www.ethercalc.org

No logins required and good for use on tablets, android phones and devices where you cannot install full software.