Paul Schreiber blogs about the tech behind the websites of presidential candidates. "So, you want to run a country. Can you hire someone who can run a website? ...Here's how the (declared) candidates' sites fare." There's a table comparing 4 candidates' sites based on HTTPS, URL permutations, IPv6, SSL rating, and other related qualities. Schreiber mentions that he will "update this as more candidates declare or sites change."
From the blog comments
HillaryClinton.com was using IIS (and no https) until Sunday morning, when they switched over.
Drifting off-topic, but as a quick PSA: The better term is "real estate agent". You don't have to be a Realtor® to be a real estate agent any more than you have to be a CISSP to be a computer security expert. It's just a trade group that does a lot of marketing and lobbying. And the lobbying is (surprise!) not always in the best interest of the general public.