Yeah, my dad has spent the last few days incandescent with rage at a system which (presumably via deceptive opt in) seems to have emailed everyone he's ever been involved in email correspondence with, which he thinks includes a number of people on cc chains he doesn't even know.
So basically, instead of welcoming someone who fits smack bang in the middle of their ideal demographic (self-employed professional with specialist expertise and a lot of old contacts but no time or inclination to go to networking events) they've got a phantom account with over 100 connections but no intention of using the service ever again.
I remember another site that grew very big on this invite model. AOL wasted half a billion on Bebo.
Time to start shorting their stock whilst reporting their emails as spam.