I can really really recommend putting a QR code on the first and last slides of your presentation. Typically 25% of the audience scans the QR-code at the end in my experience. And it makes a nice 20 Mbit/s bump in the webserver bandwidth graph. I do tell people the QR-code leads to a PDF with notes per slide btw, so that the presentation also makes sense without me.
@bert_hubert I think this is an excellent approach! It always leaves me puzzled when presenters overfill their slides with text and plots, arguing that in this way people can read & understand it later. These kind of slides lead to unbearable presentations.
Would you mind sharing an example of your slide/comments?

