Revenue creation is the only difference between Social Media Marketing and Social Selling.
One is social media activity that does not have revenue generation as its primary goal (although it may include the important activity of corporate and personal brand awareness and brand building). The other is leveraging social media to generate revenue.
If your goal is to simply generate vanity metrics - followers, likes, shares, comments, etc - with no actionable conversion metrics like opportunities created, revenue generating metrics like appointments, conversations with prospects, sales demos\pitches, closing deals and so on, then you are engaging in Social Media Marketing.
If your goal is to make a sale and to try to generate interest in your product or service that will lead to an offline conversation, then you are engaging in Social Selling.
The difference is that marketing drives awareness and sales drive revenue. Marketing is about customer education more than ever before and most buyer education, on their way to making a purchase, now takes place online. Even if a sales person picks up the phone to make an initial contact, that prospect will go educate themselves online to determine whether or not they see potential value. If the marketing team hasn't done an effective job, the sales person never gets a chance to do their job.
And that is the difference between the two in a nutshell, although in practice when asked to engage in vanity metrics so as to raise awareness of a brand's image online, this awareness of the brand does of course lead to prospects picking up the phone and asking for a meeting ........ surely a case in point for Marketing and Sales people to coordinate regularly because ultimately, isn't everyone working toward the same goal?
If you'd like to discuss Social Selling for your business, get in touch via my Contact page.