But when you change email servers, you have to manually email everyone in your contact list to get them to switch over, while Mastodon has an automatic forwarding service that switches everyone you follow, and everyone who follows you, onto a new server. This is more like cellular number-porting, where you can switch from Verizon to T-Mobile and keep your phone number, so your friends don't have to care about which network your phone is on, they just call you and reach you.
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