Timers usually count down. They are set at a particular number of minutes and lose minutes as time goes by. So they count down. For example, the timer on an oven or on a microwave counts down to zero.
On the other hand, something like a stop watch (used in sports) counts up--it counts how many seconds have passed since the start of the event. These may also be called timers, but they
On the EnglishForward, for instance, there is a time on the top right hnad of each post that says when it was posted. Is that a timer? Is this correct to you?
The timer on the site counts up from the second you post the thread.
I think I would say: The timer on the site begins counting from the second you post the thread. (Counting up is assumed; that is, we understand that the number is getting larger.)