Sure you can.<p>Depends on your target audience.  IE has vanishing small market share amongst several groups such as tech savy, non-MS developers, Apple fanboys, etc.<p>Also, if those capabilities lead to features that vastly surpass your competition it'll be easier to own majority of non-IE customers than it would be going after all customers with generic features.<p>You don't need every person with a web connection as a customer, you just need enough to be profitable/successful.