there are many theories and lots of conflicting information out there on the net on this topic. but in my opinion, soreness does = hypertrophy.
ive been lifting since i was 13-14 and im 32 now and im pretty happy with my body. i have some experience and ive tried different things so ill try to explain what ive learned the best that i can.
when it comes to building muscle the most important thing in my opinion is creating the micro tears in the muscle fibers and letting them heal. and it doenst matter whether you create those micro tears with high weights or low weights, hi reps or low reps but it is much easier and safer on the body to create the microtears with lower weights and higher reps. with higher weights you may not even be able to activate or target certain muscles properly. and it also doesnt matter if it takes you 2 hours to create micro tears in the muscle fibers or 20 minutes, which is why duration does not matter much either. its possible to get gains off very few sets or a very brief workout as long as you are able to tear up the muscle fiber. and this is why you want to be as efficient with your workout as possible. there are ways to combine certain compound exercises with good intensity to create substantial muscle tears in a short amount of time. for example, if you only did squats and shoulder presses for 20 minutes at a good intensity and keep hitting muscle failure over and over in those 20 minutes, you could create a substantial amount of micro tears over a large portion of your body.
this is also the reason why focusing on strength is a waste of time in my opinion. i see guys in the gym doing powerlifts at low reps expecting to get bodybuilding type aesthetics. or guys trying to build up their chest by struggling to bench press tons of weight instead of lowering the weight and tearing up the muscle easier. its easier and more effective to create micro tears with lower weights and there is much less stress on the joints. here is a video where pro bodyuilder kai green explains what im talking about a bit better. the muscle contraction is the most important thing, not the amount of weight you can lift.
http://www.liveleak.com/view?i=7e5_1342056496