I saw the same thing. Logged into EF and found this:

Today United Airlines has decided to remove award and upgrade class inventory from various channels, affecting ExpertFlyer. As such, United will be removed from the list of airlines in the Award & Upgrade search tool until further notice. In addition, all Active Flight Alerts for United award or upgrade class codes will be put into the Expired state. Should the award and upgrade data become available at a later date, we will again activate those Flight Alerts.

However, all other United data will still be available on ExpertFlyer including:

Detailed regular fare class inventory via the Flight Availability search tool
Flight Alerts for regular fare inventory classes
Live Seat Maps and Seat Alerts
Fare Information searches and all related fare data
Flight Status, Flight Detail, Travel Information, and all other ExpertFlyer search tools.

Thank you for your understanding in this matter and continued support of ExpertFlyer.com

-The ExpertFlyer.com Team