Neither verifying nor repairing erases any data.
Verifying only tells you what may be wrong. Repairing repairs it!
When you have repaired the hard disk you should then also repair permissions. As this not only takes ages, but the results may give you cause to panic, don't!
As long as the report ends up with 'Permissions repair complete' then, as far as permissions go, you are fine. You can ignore the various statements in the report:
Permissions you can ignore on 10.5 and 10.6:
Using 'should be -rw-r--r-- , they are lrw-r--r--' as an example, you will see the that the permissions are not changed, but the | indicates a different location. This is because an update to Leopard changed the location of a number of system components.
Poster rccharles has provided this description of what it all means:
d = directory
r = read
w = write
x = executeable program
| | |
| | all other users not in first two types
a little more info:
Before the user had read & write. A member of the group had read.
After, only the user had read & write.