I've had Skype running on some of the Linux test installations for the past couple of weeks. One thing that has become clear is that the erratic "presence" indication is not unique to the Windows client, it is also in the Linux client. I only have about a half-dozen Skype contacts left (and I'm trying my best to get them to switch to a better program), but I still get a steady stream of "xxxxx has appeared online" / "xxxxx has gone offline" notifications for most of those. Most of these are for people whom I know are either sitting in front of their computer working, so they are certainly online and active, or are nowhere near their computer, so whatever their state is, it shouldn't be changing. This bug has been reported and discussed in the Skype User Forums for years now, without ever being fixed. Just about every time a new Skype release comes out, they claim it is "fixed", and it never takes more than a day for someone to report that it still doesn't work properly. Is Skype incapable of getting this information reliably right, or are they simply unwilling to make the effort to fix it?
This might seem like relatively unimportant information, but Peter Csathy (CEO of SightSpeed) has a guest writer in his Digital Media Update Blog today, who discusses spontaneous video chats as a telecommuting equivalent to "water cooler chats". He says that the first step in such a chat is checking the online presence indication of the other person. That makes sense, you can't chat with someone who isn't present - but if the presence indication is incorrect or unreliable, you may well not be able to chat with them regardless of whether they are actually present or not.
SightSpeed gets this presence indication correct, consistently and in detail. So does ooVoo, and Gizmo5, MSN Live, Yahoo, and in fact all of the other Video/IM programs I have looked at, going all the way back to ICQ. It would be nice if Skype had people with the technical competence to get this fixed, or management who insisted that it be fixed, but apparently they are lacking one or the other, or both.