Michael Jordan, George W. Bush, Justin Bieber.... All bigger than Eminem. You crazy, man.
eh, I'm not sure about Michael Jordan. Maybe in the US, but since he's mainly known for basketball, I don't think that would translate into worldwide recognition, unlike music, which is everywhere.
I also disagree on Bush. Sure, he's well known, but no more or less than every other president, which doesn't really make him relevant.
Now about Bieber...... Maybe, big maybe. He's more of a fad though and he's been doing a lot of suspicious things lately that really doesn't make him appeal to anyone outside his fan base. Eminem has been around for over a decade and he's still rocking the charts. Here, let me give you a likely scenario.
I go up to someone and say "What is X been doing recently?"
MJ: no idea
Bush: I think he has a museum or something, but I have no idea
JB: sleeping with Brazilian hookers and peeing in buckets, I haven't heard a hit song in months though
Eminem: going berzerk! I love/like/listen to his music.
Sure, he's not as big as he was before, but when I see tons of people talk about it around my college campus, he's still relevant.
I agree with Berty6294, he's one of the top 5 people for MS to pick.