Also, in winterhold, someone took blue wool from the spleef arena. (I have a sneaking suspicion who, but not going to say that here.) Some ice over the portal was broken. A few days ago I found a piston missing from the colosseum in the old world (along with some missing sandstone. Could have been an enderman though, but I doubt that due to blocks being gone, not moved), and someone had messed with my redstone and pistons in the door to my house in the old world. Wasn't going to say anything originally, but it has started to happen a bit too much.
More also, the world is getting really crowded by spawn. Already had someone build steps to a house that actually touched the gate to my area. Also some huge stone thing is being built in the bay by my tower, which isn't bad in and of itself, just that that it ruins my view and fills half the bay. (sorry to call you out specifically, just that monument is enormous) And just in general there are people with multiple houses, all by spawn, and it's messy. Some consideration for your neighbors would be nice. World is basically infinite, we don't have to build on top of each other.