Google Invisibility Tracker

Google Invisibility Tracker informs you when a buddy of yours goes invisible. This is possible only if your buddy uses Gmail chat or Google Talk Lab Edition or iGoogle chat.

The reason is that these 3 clients use to send a vcard node when they go offline while when going invisible they send a plain unavailable presence. This means that if we analyze all unavailable presences sent by online buddies we can discover if they’re going offline or invisible. Obviously you have to be online (or at least invisible) to catch the presence.

Note that there’s a odd case: if shared status is invisible we cannot state if the chat is turned on while if shares status is not invisible we’re sure that an unavailable presence (with the vcard) means that the buddy has the chat turned off (in that client/resource obviously!).

There is an easy way to cheat this plugin: just use a XMPP client without Google Shared Status (i.e. Pidgin, Psi, Kopete) and set the resource to “gmail” or “iGoogle” or “TalkGadget” and after login go offline. The client will send a presence unavailable without vcard so the plugin will catch you as Invisible.