Yup. The idea is to create room for each of your elements. Because your basslines (they all do) use up a heap of space in the frequency spectrum, you usually end up taking notches out in quite a few places - a spot for your kick, a spot for your snare.etc. The way to do this, is look at a frequency analyzer and see where the main hits for your kicks/snares are (should be around 90-120hz and about 180-220hz, respectively). What you then do is, based on the width or breadth of the frequencies that those items take up, you then notch that out in your bassline, and anything else that might hit at the same time that could clash (think rim shots layered with snares - they hit around 1khz, but your snare has quite a bit of harmonic content up there, so it's a good idea to dip there as well).
By doing this, what you're doing is basically freeing up space, which allows you to push your sounds harder - the better you get at doing this, the more professional your mixdowns sound. This takes a lot of practise and a lot of attention - and it's best to do it as you go. As a further point - sidechaining should really ONLY be done when you absolutely have to, or as a creative tool. The only times you have to do it, is if for example your bass/kick is hitting at almost exaclty the same point, in which case you need to figure out which one takes precedence (usually the kick) and then figure out how to beef it up
I had this issue last night with a bassline in the following track:
http://soundcloud.com/subfect/the-void - the pulsing basses hit at almost the exact same frequency as the kick - but it makes no sense to have to change everything around - so I basically side-chained the EQ at 110hz, so that those frequencies only duck out when the kick is hitting, but then comes back really quickly. Gives me space, without losing power
