skift.com @skift
tnooz.com @tnooz
gbta.org @GlobalBTA
thebeat.travel @TheBeat_travel
phocuswright.com @PhoCusWright
The last two are paid content.
And of course:
tripit.com/blog/ @TripIt
concur.com/blog @Concur
(Thanks to @dmhoffer and http://www.tripit.com/blog/2014/01/15-must-read-travel-blogs-for-2014.html)