Emob78: Grimrock II was really the only one on the list that I was interested in. I get home a few minutes ago and check the sale... Grimrock II was the one up and it only had 5 left. It was gone before I even had a chance to log in.
Fate or random coincidence? You decide.
I've noticed that if you leave the GOG homepage sitting idle in the browser for long periods of time, and fire up a second browser and look at the homepage, the number of games showing does not always line up between the two browsers and can be rather out of sync. Likewise for promos which have countdown timers, the timers do not necessarily sync between two browsers either. This leads me to believe that GOG's web code might possibly pass data to the client with some hints and what it shows is an estimate, then possibly sync from time to time to resync estimate errors. Just a untested hypothesis though but I can't think of any sensible reason why the countdown could vary so greatly on 2 different browsers sitting for hours or similar.
One browser sitting idle for hours shows one thing, a second started up right away shows a different number, hit reload on the original browser and it comes in sync with what the newly started browser is suggesting that what is shown goes out of sync over time and hinting that it is an estimate and not kept up to date in realtime with GOG's servers. I'm guessing that perhaps something like this might happen with how many games are left in the Insomnia style promos too, with say - sending a count to the browser with an approximate drain rate, then the browser perhaps decrements the count artificially at that rate and occasionally syncs with the server to get the new count and drain rate thus reducing the load compared to getting a constant realtime feed.
This is all pure hypothesis on my part and may be totally inaccurate compared with reality, but it's just thoughts I've had from observation of how the site appears to work - without actually bothering to study their javascript etc. If they do such optimizations such as these, then inaccuracies could occur over time as the error rate goes up between syncs, and someone could see "oh, 10 copies are left", log in and get a sync update to reality and find out zero are actually there.
Just an idea anyway, and I want to stress it is just hypothesis as I do not know exactly what they are actually doing, but if someone does know or care to study the javascript, it'd be nice to hear what it actually does. ;)