I hope you don't actually need convincing that organic search engine optimization works. But just in case, here is a "top ten" list that should do the heavy lifting for me.

#10 – Nearly 250 millions searches are performed per day. Just on Google!
#9 – A high search rank = be found 24/7/365
#8 – Organic search results represent 85% of all clicks. Opposed to only 15% for paid listings #7 – Online marketing up an average of 8.6% a year through 2011.
#6 – online marketing nashville,Online marketing currently at 7.6% of all media advertising spending is projected to be at 15.2% in 2013.
#5 – $25B of ad spending is leaving print media and other traditional media and going to internet marketing. Switch before you competitors do!

#4 – 39% of all businesses are paying for SEO, up from 19% in 2007.
#3 – 8 out of 10 people find the company they do business with online via search or social recommendations - which play into SERPS.
#2 – You are there when THEY are looking! It's always easier to get a new customer when they seek YOU out.
#1 - By far best return on investment! Hardly anyone searchs when they aren't in the market. Only target people who are ready to buy.