People who like Pandora Jewellery?

Could someone please explain Pandora Jewellery to me please?
I understand the basic principles – I think. You buy a bracelet and add beads as you go along. To me they seem quite expensive and I dont understand what it means to “join Pandora”
Could someone please explain it to me? 10 Points for most informative answer. (dont post links, explain in your own words please?) Many thanks

You don’t understand because you’re a sane person, they’re basically for people with more money than sense. And yes, these idiots really do spend £100+ on each bloody bead