According to the Chronicle: Social Media in Admissions: No Longer a Choice:
College-admissions offices overwhelmingly consider social media important for recruiting students, and more institutions are creating blogs and online profiles, new studies show. Thirty-three percent of admissions offices kept blogs in 2007, and 29 percent maintained social-networking profiles, according to a report released today by the National Association for College Admission Counseling, known as NACAC. The report, “Reaching the Wired Generation: How Social Media Is Changing College Admission” (available to NACAC members), is based on survey responses from 453 colleges in the spring of 2007.
All jolly interesting. Two points to note however: first, the survey data is two years old and things must have moved on since then; secondly, how do UK institutions measure up?