Imagine yourself watching an interesting video on one of your favourite sites (You Tube, Vimeo .. alright, you get the idea!) and the screen of your Mac goes dark right when there is something interesting. It would take even more time to get it back to normal if your screen saver activates with a password to unlock.
This not only happens while watching a video on website but also while having a video conference on Skype and other messengers. This is mainly because watching a video on website or having a video conference without any chat or other task on the machine in parallel is not considered as an activity by Mac. It thus dims the screen after some time and starts screen saver in due time. This activity will be based on your settings in Screen saver and Energy Saver preferences.
Caffeine comes handy in such situations. It is a very small program which once clicked will keep the machine awake and force it to ignore your screen saver and energy saver preferences. Once you are done watching the video or with the video conference, you can click the Caffeine icon again after which things will go back to normal.
As the name suggests it helps keep your machine awake when you need it to. It is one tiny little tool that is a must have on your Mac
Click here to download