The gut instinct for many people looking at news that Yahoo CEO Scott Thompson listed a degree he does not hold on his resume is that it's the allegation of a disgruntled investor splitting hairs.

But consider what Thompson embellished (or, according to Yahoo, inadvertently put on his resume): a degree in computer science. As Business Insider notes, it's “a major credibility-builder in Silicon Valley.”

Stonehill College, which is where Thompson did earn an undergraduate degree in accounting, did not start offering degrees in computer science until 1983 - four years after Thompson graduated.

What may be most surprising is that it took this long for anyone to notice. The Silicon Valley culture where billion-dollar deals are sealed on a handshake also does not, apparently, put much stock in preemployment screenings. Thompson’s lack of a degree was first raised by hedge fund manager Daniel S. Loeb, who has been waging a relentless battle to shake up Yahoo’s board. Prior to joining Yahoo, Thompson was the high-profile head of PayPal, a unit of eBay, and his bio there also notes the computer science degree.

Yahoo’s official line is that its inclusion on his bio (which was just removed from its website this afternoon) is an inadvertent error. But as Kara Swisher notes at AllThingsD, “this is a mistake that goes back 10 years, as it is also on his bio at eBay, where he served as president of its PayPal unit... While Yahoo sought to underplay the controversy, it could become a serious issue for Yahoo, both from a credibility and regulatory compliance issue.”

(Swisher’s piece also has the screenshot of Stonehill’s alumni newsletter announcing Thompson’s hire by Yahoo and that he graduated with an accounting degree in 1979).

Loeb’s letter didn’t stop with Thompson: He also questions how diligent board member Patti Hart was when she screened Thompson, then goes on to note Hart changed her degree from Illinois State College from business administration to economics and marketing. Yahoo is not denying that allegation, either.

We have to wonder how many other corporate boards are quickly backtracking to double-check executive credentials - probably as many as there are activist shareholders trying to mimic Loeb’s tactic of digging deep into college transcripts.