I've said for a long time that social media really only works when you focus on adding value to other people. The average American is bombarded with 4,000 advertisements every day and we remember almost none of them. That's a lot of time, effort, and money being spent on the wrong people with the wrong message through (probably) the wrong channel.
If you're promoting a product, service, or even your own skills as a candidate for a job, remember that it's really not about you, it's about them. Change the way you engage them with that in mind. This video from Seth Godin last year really reminded me of this whole idea. If you're willing to take it a step further, make it an experience. Ze knows how to make moments that connect with people and all the moments inherently have value for the people he's trying to connect with.
Here's the video of Seth reminding you that no one cares about you: