This setting, when enabled, prevents the Search Appliance from fetching URLs
during custom "Find Similar" searches.
The /similar.html URL function (here) can
execute Find Similar searches with arbitrary URLs. The text of the
URL is needed to formulate a Find Similar query. To find it, first
the URL is looked up in the profile database. If it is not found,
then only if Prevent Find Similar Fetch is N will the URL
be fetched to find its text. By default,
Prevent Find Similar Fetch is Y, so that users cannot
cause the Search Appliance to perform arbitrary URL fetches.