Make your marketing so useful people would pay you for it.
If your competitors start copying you then you are doing something right!
Give away everything you know, one bite at a time.
If you want to measure social media ROI, stop wasting your time doing software demos and attending webinars. Just figure out what you want to track, where you can track it, think about both current customers and new customers, and go do it.
You must fight social media fire with social media water.
You must market your marketing.