>>> Hostman detects and removes duplicates.
>>
>> HostsMan also supports an exclusion list so you don't have to remove
>> blocked entries each time your hosts file is updated.
>
>Are your referring to 'overwrite' vs 'merge with current Hosts'?
>
>I am never comfortable with the concept of merge. What gets removed and
>what stays - the existing blocked item or the 'new' version.

It has nothing to do with either of those features. On the menu bar,
select Hosts->Exclusion List to prevent specified domain names from
being added to the HOSTS file upon import.