Yeah, that's the thing though, innit? You look up at the banner, you know, if you aren't the guy who created it, and you see Warhead and friends there and you think, gee, this Warhead must be pretty damn important. You scroll through some dozen threads and you see Warhead in at least half of them, either the man himself posting or someone referencing the Immortals and that's pretty much confirmed. (And why not, Warhead A.) is an awesome character fully deserving of his place in the canon, B.) has an awesome army with a bajillion pieces and a really good story, and C.) understands the value of lightheartedness when telling that story). So, obviously, Immortals are a superpower. Who else commands that kind of respect and power, really?
You've got the Assyrians? Badass AC, best goddamn capital ship I've ever seen, and a really cool sigfig (who is awesome for a lot of reasons, not the least of which, imo, is the fact that she's NOT the leader of her faction). Certainly, they've had their share of appearances, as well. Natalya is one of the best big builders here and she's a clever builder too as even her smallest creations carry a charm few others can match. Now, she's switched focus (I remember reading that you were more comfortable with the Canadians, Natalya?) to a new faction...even switched over that sigfig. The Canadia Star Legion isn't nearly as "important" or "influential" as the ASE but its not really less cool. And where do we draw the line between the creator and the faction there?
Maybe the factions of Medivo? Off the top of my head, I count three? four? players who've based characters and entire factions off of that overarching story. Legions of amazing, unique minifig regiments, a storyline that keeps expanding at a fairly magnificent rate (it may be one of the Only storylines that consistently evolves here). Several important sigfigs, some even with their own Rayhawk brand artwork. One guy spawns this world and now its fully inhabited by at least one other player and personally referenced by a couple more. It's scattered among them, sure, but I'm not sure that makes it weaker. Seems to have made it more important. Similar to what's been said about social influence, only more direct.
How about the Scythian Empire? Shadowscythe is damn prolific in LDD. It may not be "real lego" but first, he's proven himself squarely in that area anyway, and second, there's still a lot of work and creativity involved there. Those ideas, coupled with his excellent brikfic, make his faction extremely well respected. There's a huge chunk of it that doesn't actually even exist physically, but there it is.
And on and on all the way down to the little people. I've gotten several compliments on my "faction" and I'm not even sure it's even a thing yet.
So I'm not discounting social influence but...where's the line? If we say that a faction has to be as influential as the Immortals, well, I think we'll have to stretch a few arguments to get any other faction recognized as a superpower. If 100 people like one thing and 99 different people like another, we don't discount the 99. That's nearly half our demographic. That's why I think it doesn't matter. Importance is relative. I could ask all of my friends if they know who Warhead the Immortal is. Perhaps one would know, if he's been looking at the wiki since he expressed an interest. 3 or 4 would be all like, "Is he a highlander? I don't remember him..." and then proceed to bore me to death with how awesome Methos is. The rest would ask if I was talking about sour candies or give me blank looks. What I think does matter is content. If you've produced a lot of it and haven't been booed off the forums, I'd call you a success. But I don't know about qualifying a Big Ten Megacorporation list.