Where does the list come from? After the junk mail is filtered out, Microsoft looks for information in the message header that identifies it as a subscription.
What it does: Subscriptions is list of all senders whose messages contain subscription information in the message. Included is an Unsubscribe button and Outlook.com will try to unsubscribe you. This is great for legitimate subscriptions, such as newsletter or stores you’ve purchased from before.
However, many users discover their subscription list is full of spammers and fake subscriptions. They cannot (and should not) try to unsubscribe from the fake subscriptions. If the link works, it will verify your address is good (which will lead to more spam) and the unsubscribe link may lead to a page full of malware.
Microsoft added an option to Block Sender. This will remove the sender from the Subscriptions list. However, if you delete the address from the blocked list, the address will be returned to the Subscriptions list.
Until Microsoft adds a (real) Delete button, users are stuck with the spam subscriptions on their subscriptions list or adding them to the Blocked sender list. (Which is generally pointless as most spammers won;t send more than a couple of messages from an address.)
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