Marketing, Graham. Marketing.
I signed up as well - in fact, my entire family have signed up this morning, along with several other "people" I know (all of whom just happen to have email addresses that arrive in my "In" box

)
I put all sorts of different ages there, so it'll be interesting to see what differences there are in their marketing approach. The other thing all the addresses I used have in common is a desire to know the times of trains scheduled to arrive at Melksham. Sooner or later it'll dawn on FGW that there is actually a demand there...