When we were demo'd Alteryx Connect, I am positive that the person demonstrating said that users would be notified of @ mentions. Turns out this is not the case (https://community.alteryx.com/t5/Alteryx-Connect-Discussions/Tagging-people-in-comments-is-broken-in...)
Given that the Connect brochure promotes the "familiar social interactions" I find this super puzzling that tagging people in does not do what pretty much any other social tool does - let the person know that they have been tagged into the conversation.