Personally, I believe that it would not be a good business practice to either encourage people to use other forums or to allow members to promote other forums within your forum.... even though surely we know that other bitcoin forums do exist.
Technically, yes. However, if you've spent a lot of time in threads related to contentious HF's, you would see that some are constantly trying to manipulate others in addition to discussions just kind-of looping.
well opening and closing the channel requires a ( larger than normal ) Blockchain TX so unless you're going to reuse the channel 100's of times, the cost/TX on LN will not be many orders of magnitude less.
The point is to use it multiple time. Opening a channel, creating a single TX and closing it is redundant.
are second layer payments free? i mean say i want to use Lighting Network to buy a coffee what kind of fees can i expect?
They aren't free, but they should be cheaper. We can't really tell you the exact fees at this point in time as we could end up giving you information that is completely false (unintentionally).