The problem is you're much less likely to engage with or take notice of a five minute ad at the beginning of a show, you'll get up and make a cup of tea or brow

The problem is you're much less likely to engage with or take notice of a five minute ad at the beginning of a show, you'll get up and make a cup of tea or browse HN in the background while you wait. There's also not much an advertiser can say in five minutes that they can't say in 30 seconds.