BuudySpy appears to be only for Yahoo! IM clients. MessengerDiscovery can tell you if a contact deletes you I belive, but I am not certain and I'm fairly confident it doesn't let you detect people appearing offline. You do not hear a sound when someone signs in as appear offline. This is a privacy issue.
However, it is possible to do (even if it is not accurately done):
quote:
Originally posted by SpunkyLoveMuff
A while ago, I did make a small Messenger Plus! Script that detected people that were using the option to “Appear Offline” (Please do not ask me for this, I no longer have it as it was a PoC (”Proof of Concept”).
Even that did not detect everybody that was actually online, and had no way to tell if they were still online when it alerted you
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