Yes, I think there are great benefits to interest-based advertising, as you suggest. It has certainly been explicitly acknowledged by the Privacy Commissioner.
Much of the Internet is free to use, particularly the social media applications. There are some “freemium” options on some of the sites, where you can pay a little extra money for extra features, but most of the major ones that people use for hours every day cost them nothing. They are advertiser supported.
The advertising you might send off to somebody in the vain hope they might connect and that it might resonate with them is worth less than an ad that you can try to direct more precisely to someone who might actually be interested in that product or service. The availability of those types of ads does a great deal to help lift these applications on which we rely.
For users, I can tell you that we're going to see ads on these things whether we like it or not. They're advertiser supported. It's a bit like television. We might think to ourselves that if someone were to give us the choice, we would rather not see any ads when we're watching a TV show. Well, if you don't see the ads, you're not going to see the TV show, because that's what pays for it. If they're going to see ads, I think a lot of users would rather see ones that actually do have some relevance to their wants, needs, and values.