Three associates and I want to integrate our individual Drupal websites so that a user can move fairly seamlessly between them. We're all new at Drupal, so our planned approach avoids "doing it the right way" by combining modules and database tables.
Rather, we plan on simply having each site's menu system include links to the other sites, and load the selected site via Iframes so that the overall user experience is more like that of a single, integrated system. We'll adopt a common theme for all sites, and pass the user id through the HTML call (and then process it via normal Drupal code) to avoid the need for more than one logon.
My question is this: what are the negatives of this simple approach and are they so severe that a more traditional site-integration approach should be used. Thanks very much.