Expanding on my tweet:
I strongly dislike this.
My reasoning is that people often ask questions that...
- they can themselves answer by going to the project's websites. For example: "What is the LICENSE?", or
- are only of interest to them
- there's a lot of WELL, ACTUALLY... that we don't ACTUALLY need to hear, as in "you said X but I guess you ACTUALLY meant Y, am I right?" or "but why did you use X when Y is so much better?" (when they have an special non-disclosed interest in Y)
- sometimes the question cannot be answered because you need time to check the answer, so it makes the speaker look stupid and it's not their fault
- or sometimes the speaker will give you a wrong answer because they are on stage and they are nervous and you just asked them a thing they didn't rehearse and that will make them look stupid too
and therefore these five minutes would be better used for stretching your legs and leaving people's brain some time to rest and digest before asking anything.
Or maybe do as Scotland JS did past year, and have a post-talk side track where people who are interested on expanding the subject of the talk can go and discuss further with the speaker.