They sure do ;D
I actually posted recent pics on my myspace account, that I barely go on lol hubby was mainly using it to play the apps and had an account on mine and on his to get better scores or whatever, and my cousins emailed me and asked if I got implants LOL. Also I chatted on yahoo with an old friend and he asked similar lol. His exact words were "umm, something is different about you, did you change something?" I said, yea I dyed my hair brown so I wouldn't have to keep up with the lighting of staying blonde, he said "no I mean, did you have any surgery?" I said no why? lol he was so scared to come out and ask as to not offend me lol, but he eventually asked about my boobs being bigger, I told him I did it naturally, he then asked about it to share with his gf cause she was considering surgery. Last I heard she is taking PM and using a PM cream and is loving the results so far
she said she might go for the pump after she has kids in the future since it seems to work better for those who have had kids, to get her boobies back after child birth.
But yea once you get about a cup or two size difference, people WILL notice, just be prepared for the questions and weird stares lol.