Oh this is so awesome!

From now on, it's the only thing you'll see!! :)

I looked, scanned the article looking for this arrow, came back to the comments, read this, went back again, finally saw it.

The Giraffe one from the OP was super cool though :)

IMHO that is one of the main benefit of negative spaces (I didn't know the term but knew the technique): you actually hardly notice that there's "something else" and yet the logos somehow look nice. I'd say they look "soft", without knowing why.

Once you focus too much on "what's inside", it gets a bit confusing because you're seeing conflicting things (like the tree leave that is also people): but it's not a problem because it's not meant for people to really focus on.

And somehow it just works. I find several of these logos really very simple and great.

Now that this has been posted on HN I expect lots of startups to come up with similar logos ; )

You need to think of the context of that logo, which was, what, 30 years ago? The arrow meant speed in a time when post (hell, pretty much everything) was slow. And visual jokes such as this were still pretty new. It's like saying The Beatles' 'She Loves You' is simple and obvious, yeah, it might seem like that now, but it sure as hell wasn't the case back then!