Company policy requires me state this anytime I say something positive about Google. Otherwise there's the risk of it coming off as astroturfing.

I think it's better to err on the side of caution. By stating that fact you're defending Google, might be open that you work for the organisation.

It’s intentional, it’s a way to brag. They don’t need to at all. There’s a reason why nobody at other companies does that - people at other companies are normal and don’t think they’re gods gift to the world.

If you search for "Disclosure I work at Microsoft" site:news.ycombinator.com you get 300+ results.

Though Xicrosofter returns none.

It's required by company policy. Otherwise the comments could be seen as astroturfing. The policy is so strict that it specifically says you need to put a disclosure in every individual tweet, a disclosure in your Twitter bio isn't sufficient. I think that part of the rule is broken frequently though.

Interesting. Is it limited to Twitter? I can see the company fearing a backlash in social medias where you're operating under your own name (and thus can be traced back to Google) but what about anonymous and semi-anonymous forums like HN?

I re-read it, and it actually doesn't explicitly mention Twitter. It does mention how you can disclose using hashtags, which is why I misremembered it as talking about Twitter, because Twitter and hashtags are so linked in my mind.

It looks like it applies to basically any online post/comment, regardless of if it's anonymous.