I used to use that a lot on the old system.
- to check if a guy is making his first topic.
- to look at old topics to see what info he posted before and what I suggested at that time.
I can find a user's stats.
With the old system I could click the user's name and find posts in all forums.
If I search "user:ksman" there are only 49 posts.
Google says there is nearly 10,000, the number should be larger but Google may have dropped some.