I was a paid-up member for a year but let my membership lapse. Have just had a contact from a girl I was at primary school with and when I tried to reply I was told I couldn't without renewing my membership. I don't think it used to work like that - just one of you had to be a paid-up member and if someone contacted you you could reply without having paid.
Call me stingy but I'm not prepared to fork out £7.50 to send an email to someone I haven't seen for almost 27 years (and the only memory I can dredge up of her is going to a birthday party at her house and being fascinated by her extremely rude kitchen clock).