Hmmm · 9:51pm Aug 21st, 2014
Applejack - Three apples
Rarity - Three diamonds
Rainbow Dash - Three colors
Pinkie Pie - Three balloons
Fluttershy - Three butterflies
Twilight Sparkle - Six stars
Just something I noticed, not really anything important. Though it is interesting that Twilight's cutie mark has twice as many characters as the rest of them do. Could that mean anything?
Her name also has an extra syllable; hers has four, her friends' have three. "Celestia" is also four, and our near-invisible Luna has only two.
What does this mean? It could be intentional, relatively subtle importance cues. I dunno, it might also not be.
2389269 It just seems a little odd that all the cutie marks that directly came from the Sonic Rainboom, except one, have three of their respective... what's the word?
2389519
You're not wrong. I'm adding to, rather than contradicting, what you've said.
2389521 It may have something to do in Season 5.
Or it's a coincidence
2389571
I think the "greater importance" of Twilight Sparkle is already pretty clear and played out. She's an alicorn princess now, she's more magically powerful than almost anypony, and she's even started to adopt a more mentorly role towards her friends in season 4 (reminiscent of the role Celestia filled towards her).
Similarly, her cutie mark is symbolic of the intertwined six destinies of her group of friends, all centered around hers in particular.
Three items in their cutie marks could be a coincidence, or it's also meant to go along with their three syllable names and lesser significance (though their significance is still greater than Luna's, oddly).
2389600 We'll have to wait and see