At the bottom of the site, there's a Guestbook (you can't add to it, it's "full" and the sign-in function is disabled. That's the first hint that the messages on there aren't just random fans - most of them are references in themselves.
The first notable ones are the posts by @Roy_T, a username clearly designed to be a nod to Roy Thomas, most famed as Stan Lee's first successor as editor-in-chief of Marvel Comics who has already been referenced in the MCU before in Age Of Ultron's Captain America "flashback" scene. More importantly, Thomas was also one of the ekey creatives behind Captain Marvel.
He and Gil Kane revamped the original Captain Marvel (Mar-Vell) and were key to breathing new life into the character. He was also the dialoguer on the original Kree/Skrull War story arc (under the story direction of Neal Adams).
That image also leads to another couple of references...