Web-based productivity applications are great for people who are not always at the same computer: students, library patrons, most library staff. With a user name and password you can create, edit, and save documents, calendars, spreadsheets, and more. Look out Microsoft!
However if you are going to use these tools you must have a reliable Internet connection. As some Blogger users have found, if you take too long to create a post, Blogger times out and you lose your post. I have not had these problems with Writely or Zoho, but I do not use them frequently. The key to using any application on a computer, web-based or not–SAVE your work, save frequently, and save in multiple places and formats.