Marissa Mayer has a complicated history with Tim Armstrong, who's leading Verizon's talks to buy Yahoo

Yahoo is a fraction of the size of Google and Facebook, but the three companies still largely compete in the same digital advertising space.

In the eyes of Yahoo CEO Marissa Mayer, it's those tech giants, and not smaller players like AOL, with which Yahoo competes, according to a former Yahoo executive.

"She believed that Yahoo was competing with Google and Facebook," this person said. "AOL was such an inferior company in her mind."

Her disapproval of AOL was most apparent when activist investor Starboard Value pushed for a merger between Yahoo and AOL early last year. Mayer would get "outraged" by the thought of anyone putting the two companies together, this person said.

But in a strange twist of fate, Yahoo is now being approached by AOL's parent company, Verizon, in a buyout attempt. And if that happens, Mayer could potentially lose her job to AOL CEO Tim Armstrong.

In fact, Mayer's dismissive behavior towards AOL may have to do with her feeling superior to Armstrong, according to a new Vanity Fair story published Wednesday.

It writes that Mayer sees Armstrong as a mere ad-sales guy running an "ailing internet company." The two would often clash over product decisions when they were both at Google. Armstrong's college degree from a relatively small school also didn't live up to Mayer's high standards, it said.

In any case, Mayer will soon have to deal with Armstrong, as he's reported to be leading talks on behalf of Verizon in its attempt to buy Yahoo's core business. And that won't play too well with Mayer, according to the former Yahoo exec.

"Now that Verizon and Tim Armstrong and AOL are the ones that are the possible acquirer, I think that's got to be painful for her," this person said.