I worry that this might cause a cascade of information being lost. Oftentimes serious conversations are seeded by comments which may be incorrect or worthy of deletion.
If that item gets deleted, then suddenly someone else has a (valid) comment which now makes no sense. So if that person deletes their "non-sequitur" the chain will continue. Until the conversation disappeared, regardless of how valid or useful it was.
If a user has commented more than once and they delete their comment, there is no way to determine if the @ comments were directed at the first (deleted) comment, or the second (still active) comment. While this may not seem like a big deal, it leads to a very confusing user experience when you get notified that a comment you referred to was deleted, and you go to the post and there's literally nothing out of place.
Any system that has "false alarms" greatly numbs its own usefulness.
Because the system attached a comment notification to the most recent commenter with three matching letters, it means that if
- Jon B - some thing
- Jon S - some comment
- DevinB @Jon blah blah
Jon S will get notified. Then if Jon B deletes his comment, will I get notified? Probably, because it will just trace up the comment string and try to find any "@Jon" comments.
Second scenario, what if Jon S, THEN Jon B deletes their comment, will I get notified twice?
I feel that this will not be all that useful, will be difficult and confusing, and could possibly cause some detrimental conversation deletion that will be a loss for SO as a whole.