Was the query for a domain name or just hacker+news? How do we know?

Does <title> make any difference?

I don't think of this site as "Hacker News". I think of it as ycombinator, and the subdomain, news.

Should users of hackernews.com think of that site as something else, e.g. whatever is between the title tags?

A searchable list of domain names, ranked by popularity. Or even a searchable list of main page titles. Is that how some users are using Google? If so, Google does not need a full, current cached copy of the crawlable web to provide that.