1. Opt in. Why the hell not? I think it is a fair game, you train on my words, I get paid. Quite simple.

2. I guess it depends. If the increased traffic also means increased revenue, then probably yes. If not, then no. I write a lot of stupid shit and I don't want to mislead anyone into thinking that I have the answers. I don't. The summaries that search engines compile seem quite "official" sometimes and they are not a well researched and balanced answer to a particular question, thus I don't want to contribute to misinformation.