As is typical outside of big cable sports weeks, USA Network topped the weekly primetime viewership rankings, but interestingly coincident with their big Conan O'Brien announcement yesterday, TBS moved up from its typical #2 position to top the adults 18-49 primetime viewership for the cable ratings week. I haven't seen the list of top cable adults 18-49 shows yet, but two airings of Shrek The Third movie had pretty strong viewership numbers for TBS, so they may have provided the extra margin over their typical results. Update: Having seen the top 18-49 shows for the week on cable, it looks like Shrek was the added margin for TBS. It was the only show of theirs in the top rankings that wasn't typical (like Family Guy, House of Payne, Meet the Browns)
Of course, Nickelodeon was number one for total day average cable viewership.
Prime-time Average Viewers (Live+SD) Week of April 5-11, 2010
Adults 18-49 Primetime Average (Live+SD)
Total Day Average Viewers (Live+SD)
Nielsen TV Ratings: ©2010 The Nielsen Company. All Rights Reserved.