As part of my role as a marketing consultant, I support my clients during live events. This support includes twitting, posting Facebook and LinkedIn updates and engaging with the event audience online.
This usually results in some buzz, better traffic to the site and increase in social media followership. But sometimes, I can actually support the sales process in real time. Last week o a cybersecurity company I work with presented in a conference in Washington, D.C.
I monitored the online chatter and discussions around it and made sure my clients were active and present. I posted pictures (sent back to me by the sales guy on -site) and updated the audience about events happening at the booth. Then I saw a person I didn't know tweet about being targeted by a phishing attack. He found it funny this happened during his visit to a cybersecurity conference. I was this as an opportunity. It was, in fact, a terrific opportunity, because my client was selling a product which could have blocked this same attack.

I tweeted back to him saying he should visit the booth to see how their solution could help him. I then checked his profile on LinkedIn, and sent a quick email to the sales person on site advising him to contact the gentleman ASAP.
He did, the guy visited the booth and was impressed with the product, and no less than that- of us "hunting" him so quickly.
Hearing a sales guy rave about the marketing's performance is unusual, but that's exactly what happened. He thanked me and said he will definitely continue the dialog with this prospect.
All in all, a great example of the power of social media, amplified by the power of real-time action to achieve maximum effect.