My theory:
To my recollection, gatewaypundit switched over from their "rightnetwork" domain some several months ago to "thegatewaypundit". If I had to guess, I would say that for those several months, your bookmark link to rightnetwork was being redirected to thegatewaypundit, and that you didn't notice it when it happened. You click your bookmark, and the website opens, so why bother to look in the address bar to see that the url was different than your bookmark link?
Further, if I had to guess, I would say that they determined some time yesterday that the redirect from rightnetwork was no longer necessary.