The market for ad-supported software is still small, but it has drawn some big guns. Google and Microsoft Corp. each offer free and paid versions of their online-software services, respectively called Google Apps and Office Live, which businesses can use for tasks like making Web pages, using email and managing calendars. Google and Microsoft offer free versions of their services that show ads to users; Google's ads appear only in the email service, while Microsoft's ads appear alongside other online services. Users of both companies' paid versions don't see ads at all and get extra features like more storage and ramped-up support. Google says its Apps service has more than 100,000 organizations on its free and paid versions; Microsoft says more than 350,000 organizations are using Office Live.