Whilst a lot of attention is given to the use of email for direct marketing, I have always emphasized that 'non-direct-marketing' emails can also be used as a medium for marketing messages. This is even more the case in the era of 'big data'.
Recently, I purchased a pair of training shoes on JD Sports website - this is a range they sell in store, but the full range of colour and size are only available online. I received a host of emails: order received; order accepted; order arrived in store - and then this one ...
Whilst the other emails could have included marketing messages, this one - as it comes at the end of the transaction - is ideal for doing something to engage me as a future customer. As I have purchased the same brand and type of training shoe [in a different colour] from them in the past, and that they should have been able to link my home PC's IP address with the order, there is a wasted opportunity in offering me some kind of discount for a future similar purchase? Or, as the shoes are often released in limited edition colours, an offer to be contacted before a new colour goes on general sale?
Nothing like rocket science - just good old sales.
PS as an aside, this email could have included some kind of security message; e.g. ' ... collected. Was this you?'