In the rush to keep up, elite universities are lining up to join forces with a MOOC provider. Coursera, which began with Princeton, the University of Pennsylvania, Stanford and the University of Michigan in April, currently leads the field with 33 university partners. But edX, too, is expanding rapidly — the University of California, Berkeley, has joined, and the University of Texas announced that it would use edX courses for credit. Already, students in one Udacity class can get credit through the Global Campus of Colorado State University. Most MOOC providers are making plans to offer credit — and charge fees for certificates and proctored exams.