What I did to test my port forwarding back when it was needed was name the server free admin. If no one came within 10 minutes I knew it was dead.
Take redpikmin's upgrade forts tdm, most players for the past 3 days. Why? People join, then it closes, they really want to play it again so those people, plus more new people, join the next day. Then that day those new people and returning people want to play it even again, so they join the next day. More new people to the server join, as well as the day 2 people and the day 1 people. When your server is know, people tend to make note of it. My servers rise to the top of the list fast because I always host something new, even if it isn't always good. People still ask me
"Heed, can you host that space ship TDM from 1 month ago"
or
"Heed, do that avatar looking build thing with the monsters again"
A list of some of my popular servers that have been hosted within the past 2 months.
- Army RP
- Dogfight on Spring Canyon
- Jungle Planet Beast Survival
- Space Ship TDM
- Tyler's House Fort Wars