It's fascinating how corporations are tapping into the use of social media for marketing purposes. Here's an example of my Facebook account where I'm responding to a friend at USC and we're discussing careers. I happened to mention PwC with the web link and what pops up? This thumbnail advertisement. Notice though, I have the choice to remove it and also to choose a picture or no picture before clicking "send". Facebook users have free access to this utility and receive no commission for being "instruments of advertising or marketing". Versus the partnership that exists between Facebook (soon-to-be-Google) and advertisers/marketers.