Languages. I love them, but as a developer, wish everyone used English.
Here in Russia everyone is used to Re and Fwd -- but Hotmail uses localized prefixes.
So when I saw "Отв: test 1" last night ("Отв" - "Ответ" - response, answer as a noun), it almost made me fall under my desk.
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Re: you are not going to make the judgement based on the irrelevant content, are you
Not sure I got that, "irrelevant content"?
Subject is now a relevant factor in message linking logic.
I don't have plans for any additional heuristics based on recipients or dates or anything else.
Partly because of performance, partly because I want to be "done" with it, and finally, the logic needs to be simple enough for me to be able to explain it to users (if they ask).
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And yes, people do "things", and sometimes don't even know it.
Which brings us back to:
The priority right now is to avoid *horribly messing up* the user's inbox to the point where he/she *is unable to find a message*.
StR's comment is excellent: "no matter what you do, people will be confused".
And so, taking this as a given, that it's not going to be "perfect" for everyone's expectations (especially expectations that one isn't even consciously aware of!) -- this is the right thing to do.
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Finally, has anyone actually run into some horrible confusing situation because some messages, with different subjects, didn't get grouped?