ServerSeeker can track many players for you!
The bot has great commands like /whereis, which can find out where a player is or was playing!
Another command is /servers that can be used with filters to find the server of your dreams!
Join and see for yourself! The bot probably has you and your friends SMP in its database!
The database has over 90 million players tracked and more than a million servers! (and it’s growing *fast*)
This is basically copenheimer, except publicly available!
Check out our Meteor addon that allows you to use ServerSeeker directly in Minecraft:
https://github.com/DAMcraft/MeteorServerSeeker