Why is Girls' Generation so wildly popular nowadays?

[Barbie]

I mean, only about a year ago Girls' Generation was popular, but nowhere as popular as they are now. I live in the UK, and because I have been posting Girls' Generation related tatuses and commenting on the girls' wall posts, people from my school always ask me whether I'm a fan of Girls' Generation...only the other day a white girl asked me whether I like Girls' Generation and another girl is also a fan of Girls' Generation. And now everyone knows that Korea is the "cool" thing and so many people in my school know that Koreans have cool hair. Everywhere I go I see fans of Girls' Generation. I went to an electronic store once and Girls' Generation was playing on the televisions there. My mum and dad now know Girls' Generation and before I only had 5 mutual friends on Facebook who liked Girls' Generation, and now the number has increased...different people of non-Asian backgrounds are sharing kpop videos, particularly those of Girls' Generation and their name is widely recognised. EVERYONE knows Girls' Generation.

[H2SO4]

What is Girls Generation?

[confused]

I live in the US and I don't know that band. I only know one girl that is into kpop

[ME N ME!]

None of my friends ever heard of them. I have but I don't really like them anyways it's probably because all the hype is coming overseas?

[†Neko_Alchemyâ€]

I'm in New Zealand and I'm the only one that listens to Girl's Generation outta my friends and have no mutual likes on facebook. Maybe it's the trendy thing where you live to like Korean bands or more specifically Girl's Generation because of their increasing popularity outside of Asia. Don't worry, if that's the case than they'll find another trendy thing after all the hype has died down(happens all the time, remember the hype with Paramore cause of Twilight, that's died down)

[Hello]

Wow...I wish that happened where i lived...Only with SHINee, CNBLUE, F.T. Island, NU'EST, EXO, Boyfriend, B1A4, U-Kiss, i don't listen to SNSD that much...

[REI]

Well, they started to debut in Japan + SMTOWN does these around the world tours. In other words, advertisements, SNSD also did appear on American TV shows like the David Letterman Show. It's called the Hallyu wave, basically meaning Kpop getting more popular and Girls' Generation did debut back in 2007, so they've been singing for about 5 years+with predebut training, I'd reckon about 3 years they spent training before actually debuting. Also, they did release a English song. Anyways, I'm not a huge fan of mainstream Kpop, I prefer Korean Indie+ Infinite.

[TrucV.]

Being a huge fan of them myself, expect a long explanation!

Each member is different, and with SM being such a high top company, it's most likely their are known. Because SM produced pretty much every artist on the Hallyu Wave, there was DBSK, now TVXQ, BoA, Kangta, Shinee, SUJU, F(X), SNSD and of course, EXO's debut is a huge thing right now. SNSD had trained over various periods of time and plus SM has put them into musicals, dramas, and they endorsed lots of advertisements, it could because of Yoona, she has made an early debut as an actress thus becoming very popular, and being pretty and a good dancer, she got the spot as the face of the group, plus many male idols have SNSD members as their ideal types, it gives them attention but SNSD's fanbase is pretty harsh but very caring, causing attention for them. Recently, SM had SNSD debut in America with the English version of the Boys, and they appeared on 2 popular night time interviews, they also had SMTOWN concerts in international countries (France, California, Japan) and they made a huge success in Japan with their tour. Not only that, each member is currently busy with something making them known, and SNSD is known for their beautiful figures and beauty, synchronization, addicting songs and dance moves and their charming personalities on variety shows. (Many shows ask SNSD to appear on them)
Yoona- filming Love Rain drama
Yuri- filming Fashion King drama
Sooyoung- preparing to film a medical drama I believe
Jessica- finished filming her drama Wild Romance
Hyoyeon- Invincible Youth 2, and Dancing with the Stars 2
Sunny- Catch Me If you Can musical, host (I think) and Invincible Youth 2
Seohyun, Taeyeon and Tiffany- Music Core hosts and currently acting as TTS (SNSD's subunit, their video reached 10,000,000 views within about a week, showing their popularity)

I think it's because of their company, SM has trained artist to work their very best even to fatigue, and they are trained in acting, singing, dancing, etc. but SM not only focuses on talent but also visuals.