The site is far from complicated, and successfully used by thousands on a regular basis.
Like most things in life, though, there are rules in place to safeguard users and help with the smooth running of the site. To be mildly frustrated by any such, is better than to be hounded by, for example spambots, should you post an email address on a live forum.
As for replies, again, there can be numerous reasons for not getting one on a thread, but by virtue of the fact the thread is 'visible and out there', then you can always be hopeful of getting one, even if not in the timescale you would hope for.