graeme_p - 2:20 pm on Aug 16, 2013 (gmt 0)
Of course you consent to it, and a lot more. Any reasonably person knows that if you send someone an email:
1) If you send it to a work address it may be read by a colleague (say someone covering for them), an assistant, or by people whose job it is to monitor email.
2) If may be analysed and processed by spam filters on the server.
3) The recipient may forward it to someone else.
4) It may be processed on the server for modification of automatic deletion- e.g. the mail server may be configured reject emails above a certain size, or remove certain types of attachment.
5) It may be scanned for viruses, links to phishing sites, or for other security reasons.
If there is no implicit consent that messages can be processed by the receiving server, then all of the above are illegal. If there is implicit consent, then analysing emails in order to place ads, with the consent of the recipient, is also legal.