ROI of SEO vs. SEM

Which has a higher pay off – Search Engine Optimization or Search Engine Marketing? The study needs to be comprehensive depending on how much you spend for SEO vs. SEM, how long the investment in SEO is likely to pay off (some keywords, once optimized stay on top forever), etc. But there is also one critical component – how likely are visitors via organic search clicks to make a purchase versus those who visit via clicks on paid results? A recent study shows this:

Average value of visitor via Paid search : $2.38
Average value of visitor via Organic search : $1.35