Notepads / text editors / spreadsheets

TEXT EDITORS / NOTE PADS 


CryptPad a collaborative note service (freemium, no sign-in)

Collabora a collaborative note service (freemium)

Only Office a collaborative note service (freemium)

Google Keep
a collaborative, on-the-fly note service (free, but requires a gmail account)

Google Docs an advanced collaborative, online editor (free)

Etherpad a collaborative note service (free, but need to be installed on a server)


SPREADSHEETS 

FramaCalc a collaborative spreadsheet (free, open-source, )

Google Spreasheets a collaborative spreadsheet (free, open-source, )