What is with the nostalgia craze?

Hello Kitty collection from MAC

This week, MAC launches its highly anticipated Hello Kitty collection, complete with an online charity auction of designer clothing inspired by the Hello Kitty collection. Expect this collection to sell out immediately.

Of any item with Hello Kitty's face, here's my favorite:

Hello Kitty HK-AK-47 with hand-crocheted cover for shoulder stock

What is with this craze for themes based on favorites from childhood? Stila has a Barbie Loves Stila collection in honor of the doll's 50th anniversary - MAC had its own Barbie Loves MAC collection two years ago. Too Faced has a Smurfette collection, which is sold exclusively through Sephora and Sephora.com.

With the nostalgia craze in full swing, might we expect a revival of Tinkerbell (not to be confused with Disney's Tinker Bell) cosmetics?