I didn’t realize Clash of Clans is only from 2012. The first time I played it wasn’t that long after it came out. I also didn’t realize that I’ve seen and played most of the things that inspired it. Some things had to come together for a clash-like: tower defense, the arrangable map-village, and anonymous attacks. Here’s how I see that stuff:
To have a huge number of players, you need the internet. In the ‘70s you could dial-up to GEnie, CompuServe or AOL; in the ’80s anyone in college could get on-line, but that still wasn’t a lot of people. The internet wasn’t public until 1995, and Search (Google) wasn’t until 1998.
The first massive anonymous attacker I know of was free browser game ArchMage, in 2000. Your kingdom was just a few stats – mostly how much land you owned. The interesting thing was there was no world map, so you had no neighbors. You just had a list of people near your power level who you could attack. Most of them will rise or fall off the list by tomorrow. You were allowed to attack someone a few times, until they were knocked off the bottom, but players considered a double-attack as unsportsmanlike (you’d get pounded silly by every other player if you did it.) In practice, you attacked random people, one time each.
When you beat someone, you stole some of their land. That’s a great example of the backwards fake-realism clash-likes have today. Of course in real life, land is the realistic thing you steal — from your neighbors. But it makes 0 sense in a game with no map, attacking random people. ArchMage boldly went with it, and the players accepted it.
FaceBook didn’t add support for large games until 2008, when we got the MobWars, PirateWars and so on. Those games borrowed the anonymous attacking idea, and added endlessness. Normally, games have to have a winner. In ArchMage, the goal was to survive casting a very expensive, days-long “I win” spell with an “everyone is allowed to attack me” side-effect. You can’t have a game without a winner. Or so we thought. Facebook showed that you can. Just play to grow. If you make it to #1, or the top 100 … be proud and see how long you can stay there.
Two more things, tower Defense and an arrangeable village, came from the PC game WarCraft way back in 1995 (not World of – just WarCraft, the solo or 2-player RTS.) The upgradable buildings of clash-likes are copies of the ones in WarCraft. Even the upgradable Town Hall came from there (a building that does mostly nothing except unlock other things.)
Tower Defenses came from WarCraft in a funny way. Most of the single-player missions were about growing quickly, scouting and harassing the enemy to slow them down, building a few defenses only when you needed to. But some missions were just early waves of tough enemies. The only way to win was to build lots of defenses to hold them off. Those were just a fun break from the real missions, but we realized you could make a game with only that.
2009 had a brief craze for browser tower defenses. I didn’t play them, but I remember students going nuts for those sites, with all sorts of rules for tower-types, making paths, flyers… . Plants vs. Zombies is the main survivor of all that.
BackYard Monsters put tower defenses and endless random attacking together in 2010, on FaceBook. You may have heard Backyard Monsters was the inspiration for Clash of Clans and scoffed. I did. But you can look at pictures of bases and read strategies. Clash of Clans is clearly a dumbed-down copy.
In BackYard monsters, defenses were strong enough that you were expected to grind them down over several attacks (with the possibility of someone sniping a 1/2-destroyed base from you.) Attacks had a period at the end only for previously-placed troops to fight. The rules for getting a defensive shield were more complicated. Clash of Clans dumbed it down for the winning formula: quick sessions; simpler in general; freemium; skew younger; an App instead of browser-based. And, I’m not completely sure, but I think they were the first cell=phone game to show television commercials.