What's a "commercial"?

Is that one of those things that pops up during a show I'm watching, in response to which I hit the mute button, and either see what's on another channel or get up and take care of some things?

Eventually those annoyances go away and I get back to watching the show I'm interested in.

Wait a minute, oh yeah, "commercials"! Those are the useless bits of uninteresting and often insulting baloney that I delete when editing a DVR recording.

OK, now I know.

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