[Brekkie]

Nope, less than 100,000 watch the live feed at any one time, but like the news channels for example, people dip in and out of it as they please, meaning over the week the number of people who actually watch the feed for at least 15 minutes or so is actually in the millions.

It affects the highlights show because it's effectively a 24-hour promo for it. People are more likely to watch the highlights if they've caught a few minutes of live action earlier in the day, or if something which happened live has created a bit of a buzz online and in the press to generate interest. Without the promotion people aren't reminded BB is on, so just don't care if they miss the highlights that night, and ultimately don't care if they watch any of the series at all.