Use this feature to allow or disallow senders that use hosted web based email readers for wumbers which you have created and flagged as restricted to specific locations. A location can be either a region (state or province) or country. wumber can not accurately determine the real location of users who send you email using hosted web based email readers.
Typically the wumbers that this may apply to are wumbers of the following types: (Although you can apply this restriction to any wumbers that you like)
You may use this setting when you are asking or relying on the sender to generate a wumber while seeking to restrict those wumbers, senders and who creates them. You should demonstrate some caution in using this feature because you may be excluding a large number of emails from users you exclude. e.g. If you are seeking feedback from users in the USA, excluding Gmail users may limit who can send you emails on those wumbers.