Moonves has made clear that CBS now looks at same day plus three, same day plus seven and same day plus 30; and they've found that generally, all programming on the average doubles their audience with plus 30 playback plus downloads and streaming video. (CBS uses I-Tunes, Hulu plus, and CBS.com for post live broadcast since they do not offer cable "on demand." (and the CW half owned and all managed by CBS follows the same policy)
The advertisers are at live plus three days at the moment, but CBS is pushing hard for a switch to live plus seven days in the short term, and they're also pushing for more complete measurement for advertisers to use live streaming, downloads, and online viewing at websites to be included.
The other thing to keep in mind is that a number of basic cable and pay cable channels are airing original dramas, etc., on Sundays, and it's a bear to program my cable DVR for Sundays, especially with the NFL overruns. (Generally I'm having to record the first same-night repeat for Sunday cable shows; there's three shows I normally watch over the course of a week that I have trouble catching consistently that are on a network, and for those I'm having to use alternative viewing.