You might have noticed that recently FB added a new feature in the chat to show whether the other party you are chatting with have seen the messages you send or not. This is a cool feature for some extent as long as I can check whether my friends have seen the message I send. But same theory applies to me as well. I personally do not like this much.

There are plenty of other ways to avoid a person in FB. Simply I can make myself offline to that particular person. But let’s discuss about something really wobbly about this feature.

Technically speaking this seen feature can be implemented in many ways. And also a real question I have in my mind is ( and FB did it in a very sneaky way) to know whether FB assures that the other person read it or not. The answer is No.

I tested few scenarios of this ‘seen’ feature.

The rule of thumb is, FB detects the seen when and only if your browser tab on which FB is loaded and the chat window of a particular chat are open and in focus.

Simple.

And FB says whether the user has seen the message or not. It doesn’t say anything about whether the user has read the message. Because FB sends the seen acknowledgement to the other party approximately after 8 – 9 seconds from the time it got the focus event fired. In some cases this time is very short; something between 1 – 3 seconds. But it doesn’t bother about the length of the message whether the message can be read in 10 seconds or not. So it just says the users has simply seen the message. It makes perfect sense.

In Windows 7 we can hover the taskbar icons and get the full snap of the windows we have opened. From the OS perspective this is not focus. This applies to FB as well. Because technically in FB this feature works on Javascript focus events which get the focus signal from the browser, where the browser get the triggers from some sort of a system call from the OS.

So you can use this method to read the messages without getting caught. 🙂 but this is not always possible and easy.