According to YouGov's BrandIndex, the perceived brand image of the major cable news networks has remained fairly constant in recent weeks, despite the small jump in viewing linked to the missing aircraft story.. The BrandIndex Buzz Index compares consumer perceptions of brands, and looks at the net difference between positive and negative comments.
As the graph shows, only Fox News has generated a net positive "Buzz", and seems to have more consistent values (in the +4 to +6 range) in 2014. None of the other measured cable networks generated a positive Buzz value over the measured time frame. CNN's perception score seems to have bottomed out last June (hitting -17), before making it back to a -4 score in October 2013, with consistent fluctuations after that. Consumer perceptions of CNN Headline have largely tracked those of CNN. Consumer perception of MSNBC has been very consistent since the start of 2014, with scores in the -9 to -10 range. That suggests the audience has pretty much made up its mind about MSNBC, and the network hasn't been able to do much to shake that overall negative impression. Since many of the big swings seem linked to major news events, it might also suggest that MSNBC's specific coverage of news doesn't change viewers perceptions about the network.
Source - Despite disaster coverage CNN perception declines, YouGov BrandIndex report