The whole point of this thread is if you have a interest in a chick you need to say something right away or you will get friend-zoned forever. The longer you wait the greater chance of being friend-zoned and that chance is oh so small. Sadly I know from previous experience.
To be fair, it doesn't have to be "right away". However, an interest MUST be expressed.
One can't expect to have a girl fall for you just by being nice to her.
Similarly, even after initial interest has been expressed, continuing to be nice while out on a "date" will not lead to desired results.
While this isn't true 100% of the time, it's usually up to the guy to "initiate" the crossing of the romantic line, and this usually involves (*gasp!*) making a move.
It's always risky, it's often awkward (even when it goes right) but it's damn near unavoidable.
There is virtually no conversation one can have with a girl that will guarantee that you can make physical contact with her risk-free, and trying is far more likely to have a negative than a positive effect. ("What's wrong with this guy? Why doesn't he stop implying that he likes me and just do something already?")
Is it fair that all this pressure is on the guy? No, but for now at least, that's the way it is.