As a related data point, I had a post go viral today on Google+ (~500 +1s, 100 shares) [1] and after about an hour, the most inane comments started piling on.

"hello"

"hi friendz"

"hi"

"Every one how is the day?"

"What's the topic for today, can any one tell me? Please!" etc etc

I can explain the timing. It presumably hit "What's Hot" so they all saw it. But like OP, I don't know what to make of it. Maybe one of the OP's theories, maybe all of them.

1. https://plus.google.com/106413090159067280619/posts/ZFTKZQfj...