I have the same problem. It's just people mistyping addresses. When I chase it down, it always turns out that they're looking for "${firstname}.${initial}.${las

I have the same problem. It's just people mistyping addresses. When I chase it down, it always turns out that they're looking for "${firstname}.${initial}.${lastname}" or they left off some number. Gmail doesn't allow people to register accounts that would collide with someone else modulo dots. My solution: create a filter that matches "to:${firstname}.${lastname}@gmail.com" and archives those emails in a separate folder.