A recent report from the job site Glassdoor is not really interesting for its ranking of the best CEOs to work for.

Sure, LinkedIn's Jeff Weiner is No. 1, while last year's top CEO, Facebook's Mark Zuckerberg, dropped to No. 10.

And Twitter's Dick Costolo didn't make the list at all, but possibly because not enough Twitter employees wrote CEO approval reviews in the past 12 months to qualify for Glassdoor's study. Maybe they were too busy, what with the IPO and the company's rocket-like growth.

But the ranking is valuable for what it says about Silicon Valley; eight of the top 50 CEOs on the list are here, after all. What struck me reading the Silicon Valley CEO employee reviews is that intangibles -- a CEO's likeability, their sense of mission, their ability to include everyone in that mission -- matter here, maybe as much as compensation.

And when Glassdoor looked at employee reviews in other industries, the desire for a CEO like that wasn't as apparent as it is in Silicon Valley, said Glassdoor community expert Scott Dobroski. For example, employee reviews for Lloyd Blankfein, the CEO of Goldman Sachs and No. 8 on the list, tended to talk about his "optimistic and motivational energy," which makes sense in the wake of the financial crisis, Dobroski said.

The top CEOs in Silicon Valley "have a very clear vision for their company where it is heading in the short term and long term," he said. "They communicate very clearly where the company is going, how the company is going to get there, and how every single employee is going to play a role."

Since it came online in 2008, Glassdoor has become the valley's watercolor, a fascinating window into the work cultures here. Reviews are anonymous but must meet Glassdoor's community standards and contain both a pro and a con, or face rejection. That may be why one Google employee jokingly complained, to fulfill the "con" requirement, that "there are not enough trees in the offices and the fish tanks get dirty sometimes."

A company's Glassdoor reviews are a must-read before a job interview, and it's become a way for employees to signal to management when something isn't working. Companies know this and follow their Glassdoor ratings and reviews closely, like a bagel shop watches its Yelp comments. Some advertise job openings on the site alongside competitors' employee reviews.

"A lot of companies are really scared by the reviews," said Jessica Miller-Merrell, a former human resources director at OfficeMax and now a HR consultant based in Mountain View who occasionally writes for Glassdoor. "These conversations were already taking place. They weren't public. Companies can't ignore these conversations any longer because Glassdoor is such a destination for job seekers and employees."

Sure, Silicon Valley's workforce has a lot to say about the quality of food in the cafeteria and office jerks.

But the general gist of employee reviews here is a thoughtful discussion about the company's execution of its mission and whether the firm recognizes the importance of each employee in that effort.

It's a message that often emanates from the CEO. In that respect, LinkedIn's Weiner, who gives biweekly, all-hands talks, gets high marks. (Like Twitter's Costolo last year, Weiner didn't appear in the top 50 CEOs last year because LinkedIn didn't meet Glassdoor's threshold of having a certain number of employee reviews). One reviewer praised the company's "culture of complete transparency," something that is echoed in other employee reviews particularly Facebook's.

Facebook's Zuckerberg probably fell 6 percentage points this year because some employee reviews flagged more of a bureaucratic feeling at the social networking giant and the addition of young middle management, Dobroski said.

If Glassdoor matters more than ever, you have to wonder if some firms try to game the system. One LinkedIn reviewer added: "P.S. don't email every employee to get them to do a review here on Glassdoor." Dobroski says that if they see reviews that are too similar sounding or if they suspect any incentives were offered for posting, the reviews are rejected. But asking employees to post a review is fine.

Silicon Valley firms are like little kingdoms, worlds onto themselves with royalty, quirky cultural norms and shared anxieties. Employees here want to feel like a part of a mission and will tell us on Glassdoor whether that's how they feel.

Contact Michelle Quinn at 510-394-4196 and mquinn@mercurynews.com. Follow her at twitter.com/michellequinn.