Can’t speak for Mozillas multihop implementation, but in general I can tell you that the concept of having multiple tunnels together does in theory make your comms more private. If a 3rd party were to try to MITM you, they would have to breach both tunnels to read your data.

This was back in 2008, before any of those existed.

I used to use firstname@lastname.com (The benefits of having a rare last name), but I found that the work behind managing the email server myself wasn’t worth it. I could probably have outsourced the hosting and spam filtering to Google or the likes, but then I might as well use my lastname@gmail.com address.