You can have multiple BTC addresses. You can have as many BTC addresses as you want. I suggest using a new BTC address for EVERY transaction.
I (everyone) always read that argument, but think about it ... that is pretty problematic.
Assume BTCs have conquered the world and every shop accepts them, so you can go out and pay for stuff.
How do you think using new addresses improves your anonymity?
In order to spend coins from the new address (the one you just made to improve your anonymity) you need to send coins there ... meaning I know where these coins came from ... meaning if I know one of your addresses in time and with afford I
can track you ... every single transaction you did or will do in the future.
Pretty scary don't you think?