Thursday nights used to be one of the evenings for television’s highest profile shows and most expensive commercials, says the Wall Street Journal [Note that the WSJ is behind a paywall and you may be charged to read this story.]

But for the first four Thursday nights of the current television season, viewers between the ages of 18 to 49 years old have declined about 4.3% from a year earlier, the story notes.

That means a loss of 2.2 million viewers, resulting in an average of 48.5 million people between 18 to 49 tuning in to any broadcast or cable channel on those nights. The decline, however, could be part of a broader trend, the story notes.

For instance, the number of viewers between 18 to 49 has declined 2.7% this season, which some analysts suspect is due to online video and computers. But the potential effect on Thursday nights could be big, given that advertisers often pay more to secure commercial time on Thursday nights to reach consumers as they make plans for the weekend, the article says.