Enterprises need the time to set companywide policies for browser deployment and possibly recode any intranet sites that are not compatible with the new version of the browser. Similarly, public Web sites need the extra time to ensure that their sites are compatible.

Even when Automatic Updates is turned on in November, it won't be made immediately available to everyone. Rather, it will be a phased rollout, and IE7 will take three months to be delivered to desktops worldwide.

The exact speed of the rollout will be determined by the number of support calls received by Microsoft about the new browser. Microsoft said it decided to do a phased rollout so that it could properly staff support centers devoted to IE7 questions. The more support calls it receives, the slower it will deploy the browser via Automatic Updates; the fewer calls it receives, the faster it will deploy.

The exact dates and times of when individuals will receive Automatic Updates will be determined randomly by algorithms on Microsoft servers.

The update feature for IE7 will work slightly differently than other automatic updates because Microsoft believes that people should make a conscious decision before installing a new version of the browser, rather than having it happen automatically behind the scenes. So even those who have configured Automatic Updates to install software automatically will be asked after the download is complete whether to install the new browser.