The other day when using iPhoto on his MacBook Pro my partner saw a weird photo album show up named after some guy we never heard of. Inside were photos of a party going on in a kitchen that looked a lot like ours, so it was clearly someone who lives in our (very large) apartment building. We copied a couple of the photos but the album suddenly disappeared. The next day, the computer was acting very flaky-- losing connection to the wifi over and over, and Photoshop crashing all over the place. I became convinced he was hacking into our router and found out where the guy lives and confronted him, but he seemed genuinely not to know what was going on and freaked out when we showed him his own pictures on our computer. Everyone has since changed sharing settings and wireless passwords, but we realized we can't even see each other's wireless access points (we're a few floors apart and the floors are reinforced concrete) and they were always pretty secure anyway. How could this have happened??