That's interesting, because I block analytics and some other Google domains and I use Bing.
Why push SSL so hard for sites many of which are just public info anyway? Because then you can't really use proxies so almost always 1 connection is 1 person.
The HTTP connection timeout is like 15 seconds or less in popular software. One of the justifications for SPDY/HTTP2 is that with one connection it can be kept open for many minutes or even hours without using too many resources.
Instead of many separate, possibly proxied connections to doubleclick you have one connection that lasts maybe even a whole browsing session. Google may not need this, but it's certainly better for them.
