Forum:What's the whole point?

ok, i am gonna write down the rule(a part of it) just as it is stated in the rulebook>"summonig a monster(.......) is not an effect activation and therefore you cannot respond to this action using a chain".But what if i use a trap hole?isn't this considered a chain? Moreover i've read that one can also use compulsory ev. device and stuff but that would also create a chain>So ,finally, what does this rule prevent you from doing?I would appreciate it if someone could explain it with an example..... Thanks in advance