The Tor client selects a small list of "Entry Guards" and uses only them as entry nodes. I think this change was made two-three years ago. This was done to pre

The Tor client selects a small list of "Entry Guards" and uses only them as entry nodes. I think this change was made two-three years ago. This was done to prevent the problem whereby anyone using Tor for long enough would eventually connect to all entry nodes, allowing anyone else to set up an entry node to gather a list of most of the persistent Tor users.