The whales are basically the biggest fish on steemit.
Basically

There are minnows. Us, the small fish. Our upvote gives a cent at best.

Dolphins, they have a decent amount of steempower. Their upvote values at around between a few cents and a dollar.

And Whales, they have massive amount of steempower. When they like something, YOU'LL know. When they like something, you'll see it under "Recommended, Hot, Trending", and pretty much heading every other sexy category, with a good number of monetarily valued digits under them.

People follow them around (I'm also guilty) in hopes of getting their attention and hopefully an upvote or two (can you blame anyone?)