Trustbusters could have these Windows XP features in their crosshairs:
Like the Net browser, this feature will grow to support a variety of new services, such as programs that let engineers on different coasts work on the same blueprints. Trustbusters want to ensure that rival services aren't squelched.
This complex technology forms the infrastructure for a variety of new subscription services. For example, Expedia hopes to use it to alert travelers when their flights are late. Critics worry that it gives Microsoft too much power.
This music and video software is going to become a cornerstone for new products and will be increasingly important to consumers. Antitrust cops are afraid that Microsoft's version will kill competitor RealNetworks.