Using Google Docs is like using an interactive notepad. One of the advantages is the ability to collaborate with peers, students, or other users. Once the document has been created, the users can simultaneously edit the active document. This eliminates the need for multiple e-mails and confusion over which version is the most recent (updated) version of a document. This would be effective in a high school or university classroom where discussion could take place and students can constantly update and change a group project seamlessly.
A disadvantage of using online productivity tools such as Google Docs is the constant need to "refresh" while others are actively editing in order to see the changes. Otherwise, multiple users could be editing the exact same portion of the document, wasting time and ending up with a product that doesn't make sense.