jimw
Contributor
I forgot the name of the site (and there may be more than one), but I recall one that features tracking historical airfares with the idea that you can see trends and figure out the best time of year to purchase a fare. Beholden to Delta here in Atlanta and greedy for Skymiles (or Skypesos as they've been called), I've gotten pretty bad about shopping for airfares.
FlightAware - Flight Tracker / Flight Status / Flight Tracking
I used this one to monitor Insel Miami-Bonaire flights a few years ago--over a few months they averaged about 1/2 hour late.......They also publish a newsletter of aviation stories and plane pics that I've gotten since then! A dive buddy who flys for JetBlue uses it to check on his flights on other airlines commuting to JFK and home.