Simple Thinking Works.

First of all, no i haven't adopted a Polar Bear. But it's possible to adopt anything from a Polar Bear to a Donkey these days.

This appears to be a simple and straight forward idea but look at charity advertising on the whole and it's actually a lot of cleverer.

How do you solve a problem like getting people to give to charity? Give them something back.

You never meet the animal you adopt (i assume they don't actually exist?)
But it's a brilliant idea that gains your initial interest and then maintains it for a significant period after the original donation.

As Dave Trott would say, simple preditory thinking. Executed brilliantly.