Glad you asked. I've been playing it for 3 years now. I first thought, that woah, that's lame.. But then I bought it and saw it in another perspective. You can build any building you desire, and play a technician with the Redstone wires and their complicated systems. Have your own farm, have your own kingdom... The possibilities are endless. You can play on hardcore survival, trying to keep alive and build your resources and base. Also, the multiplayer is awesome; On a popular server you can found your own city and have players living there, by the city's rules, you've made. You can also PVP with swords and bows and potions etc. Also, some server's have a mob arena which can be a big arena or a maze, with zombies and other hostiles everywhere.
It's also very, very easy to have your own server for free, and buying one isn't too expensive either. If you're server runs with Bukkit (it's a bit harder to install than normal server) you can choose from thousands of plugins (small modifications) or actual mods. I had a server for a year, for 20 players/12e/month, but I was there most of the time alone, so I recently shut it down.
From the game name ratings, minecraft is one of the games with a good name. It sure explains what the game entails as there is a lot of mining done in the game. The name is also so easy for someone to understand what is it is all about when you first hear the name before checking the features.
Let me tell you a little about the game. It's a game you have to mine for ingredients to make/build things. If you want nice tools that last awhile, you have to mine for awhile until you find diamonds. You can build anything imaginable. I have a map that I built a rainbow on. To do this, you must harvest lots of wool from sheep, and dyes from the mines to dye all the wool different colors. (It's a long process, but very fun to do). I have a town built, that includes several houses, a jail, a motel, a farm, and I'm still building. Speaking of a farm, you can breed animals, grow wheat, melons, and pumpkins. Don't want to build your own town? Go searching above ground for one of the many NPC Villages. Don't venture out at night though, you'll get beat up by numerous monsters including but not limited to creepers (which I call boomers because that's what they do), spiders, skeletons, zombies, and more.