Sending a CEM to an email obtained through a social networking web page is permissible under CASL. An email displayed on a social networking site would be considered a conspicuous publication, and CEMs can be sent to these emails, without consent, if (i) that individual has not indicated that he/she does not wish to receive unsolicited emails, and (ii) if the CEM relates to the recipient’s business role and/or function.
Although there is no case law to this point presently, persistent emailing will likely not be impliedly accepted, as it would be more than one message and not a message so our recommendation is to send an inquiry email to your counterpart asking if he/she would like your solicitation (e.g. to be added to your newsletter) wait for a response, and then add. This will add more steps in your process, but these steps are recommended. However, a simple like or a follow on sites such as Facebook or Twitter is not express consent for the purposes of CASL.
Within that media platform you would have only obtained that TYPE of permission but it does not follow true documentation which is required by CASL. Therefore, from a common-sense perspective (until the legislation comes into force), you cannot simply move all those individuals who have liked or followed you on a social networking site onto an email list unless they have expressly opted-in; otherwise it would be considered spam.