Template:To
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To Example:
This template will alert users using the Echo notifications system (found at the top of every page for logged in users that have not switched off this feature in their user preferences) or at Special:Notifications. This allows users to be alerted when a conversation is potentially relevant to them without having to watch a potentially busy page. Alternatively, if users want to call your attention to something but don't want to have to post on your talk page, then they can simply insert {{To|USERNAME}} to give you a notification.
Up to 5 users can be specified when using the template, {{To|USERNAME|USERNAME2|USERNAME3|USERNAME4|USERNAME5}}.
View similar notification systems on Wikipedia.