It seems it'll calculate each user for only once,
that way each if someone frequently comes back,it's still not shown.
What do you think of this idea,bad or good?Any better solution?
It's a good idea, and I for one am glad it's implemented this way. To me, this gets the genuine level of interest in a question.
When I ask a question, I will frequently revisit it throughout the next hour or so, looking for answers. That would unfairly jack up its popularity (measured in views) if the counting weren't implemented this way.
By the same token, I'll also frequently revisit questions I've answered or commented on, for much the same reason. And again, by only counting a unique user's first visit, the view count remains an accurate gauge of the question's true popularity within the community.
This is implemented with a sliding time window by IP address, pretty standard stuff.