From the release:

Last night's Democratic presidential debate hosted by ABC News, the National Constitution Center, and WPVI-TV was easily the most-watched of the 2008 presidential cycle. The debate averaged 10.7 million Total Viewers, a 3.5/9 among Adults 25-54, and a 2.7/7 among Adults 18-49. The debate was moderated by ABC News' anchors Charles Gibson and George Stephanopoulos at the National Constitution Center in Philadelphia and aired from 8-10 p.m. ET/PT on the ABC Television Network.

For the 8-10 p.m. time period, this marks ABC's best Total Viewing audience since 11/28/07, its largest Adult 18-49 rating since 2/27/08, and its best Adult 25-54 rating since 1/9/08.

The first hour of Wednesday's debate ranked first in its time period among Total Viewers, Adults 18-49 and Adults 25-54. Up against Fox's "American Idol" and an original episode of CBS' "Criminal Minds" at 9 p.m., the debate retained 96% of it Total Viewing audience, retained 100% of its Adults 25-54 audience, and grew 4% among Adults 18-49 from the first hour to the second hour.

Also, George Stephanopoulos defends the debate in an interview with the Politico.