The internet used to be a social network.
You used to be able to email people you didn’t know: you’d see an article about a topic in which you have some expertise, and you might want to email its author.
Basically, you can no longer do this: you might be able to leave a comment on the article, which is no good if you want to write in private, and in any case this nowadays involves signing up with some awful third-party identity integration service like Disqus or WordPress or Gravatar or whatever, and your message can get lost in the fray of utter bilge in the comments section, whereas it might have got read and led to a discussion if it had gone by email.
Your other option is sending a message on Twitter, but that’s got all the same problems as the above, but limited to 140 characters.
We’ve certainly lost some of the original benefit of the Internet as a facilitator of discussion, at least between strangers.
If you could bear reading this far, you should follow me on Twitter: