One thing that strikes me with some shopping websites is the inability to change your email address and you have to email the support team to get it changed. But the wooden spoon goes to Pixmania for emailing me back and saying, no problem, we've changed your email address to the one you had originally, rather than the one you wanted changed to. So, I've emailed them back, lets see if they can get it right this time. Orange are the worst offenders, try changing your contact email address, the website says no, come back later..... 3 months later, I've emailed them twice now, no reply, but they did call me to upsell to a contract phone. I'll just keep emailing them. /rant over
I suspect that as the email address often ends up being the Account ID you are effectivley asking them to change the Primary Key on your account record, that means they have to cascade that key change through every table that keeps records about you, bad data design if that is the case. Most modern membership and authentication systems use surrogate keys (they number your row in the database) as the Prime Key that way they can change anything on your record without worrying about relational integrity. Others I suspect don't allow changes to email address as it can be seen as a security issue, if the account is compromised in some way then changing the email allows the hacker to completley divert all notification that you might have received that might have alerted you to the hack in the first place.
