Basic explanation

If this option is activated all the users who view your profile and did also activate this option will be saved in your list of visitors.

Only one visit per hour and user is saved, which means it takes at least an hour after a visit to count another visit by the same user.

Every visit is saved and shown for 7 days, as Power-User the expiration time limit is extended to 30 days.

Visiting other profiles

If you yourself view profiles and you and the other user have activated this option you will also be saved to the list of the users visitors - which profiles were visited by you and if your visit was visible is accessible in "Your visits to other profiles".

Meaning of visits

A visit to your profile means somebody noticed your profile and opened it - yet why or what he or she looked at remain unknown to you.

Therefore you should not automatically conclude that a visitor has a special interest in you. If you happen to like the profile of your visitor you can of course decide to contact the person - but you should not be disappointed if he or she has no interest in you.