Get a site like Enjin that has Minecraft integration. You can see how many people are online, set up a server shop where people can /buy things in game with forum points they earn by participating on the forum, and depending on the type of Enjin account you get, it may also come with free teamspeak (though I notice most players use Discord these days...).

Good luck.

You'd need a plugin of some sort which can provide this information to your website scripts.