why do companys use Social Economic Classification?

[Ally]

i understand that companys use this list so that they can classify and catergorise social groups, but WHY do they need to do this?

for example why would a media company like the BBC need to do this?

[Sipra M]

It necessary for marketing purpose. To know the customer segment.
Yes, BBC also need this to know who are the customers watches BBC and accordingly news, advertisement, talks etc. are taken.