well ...
if I ignore MS Sharepoint (this post is really not about sharepoint but zoho) ... on one side I think this is really good idea, but and I might get some negative comments for this statement ...
WORD/EXCEL in web browser are still unfriendly and don't really work for any complex documents/spreadsheets, I hope this will change with HTML5. The only good (not great but good) web based Word I saw was flash based acrobat.com