>>863
It's a polite way to not bump a thread and yet make a post that is either a) off-topic or b) simply not all that noteworthy.

It is not a form of thread voting or showing one's displeasure with a thread. That is a form of sage usage that originated at the Fourth Circle of Hell.

Also, it is pronounced "sah-gay" rather than "sayj", therefore, the correct gerund form of sage would be "sage-ing".