Facebook beat them to it... that's the whole reason for tagged images imo. Then they can relate identities with each other and with exif gps data to track their movements over time.
HN discussions tend to devolve into rants about privacy. There are a lot of repeated discussions that occur here. They overwhelm the discussion about the actual technology
Also, my own personal privacy is less secure if it's a relative inconvenience for employers. If everyone but me gives up their privacy then there's more pressure on me to follow suit.
The argument even doubles back on itself. If these comments aren't interesting to you... don't read them. Embrace tree-style collapsible comments.
You can learn lots of interesting things by invading people's privacy.
I responded to the argument you linked. You're avoiding a more interesting discussion on the topic. Push the [-] button and move on. Your comment is blatantly hypocritical:
"Every time X is updated people complain about X; those people ignore the details of the update."
"Every time people complain about X other people complain about them complaining about X; those people ignore the details of the complaint."
That's because the privacy implication of the technology should be part of the discussions on the technology... technology is not neutral, the way its used and the privacy implications are significant.