This is a descriptive report and doesn't show much insight at present. I'll update it with more info over time. In the meantime, I can use your help ... Let's put "social media" and "crowd sourcing" to the test to make this graph as accurate as possible. I've estimated Linked In's total size for the time of its launch 5/5/03 to April 2010. You can help us get more accurate data... Send me the date you joined Linked In and your member number. Tweet @BESegal, or em BruceESegal@gmail.com I'll update this chart with the collective data. How To Find Your Linked In Join Date: Linked In shows you your join date on your "Settings" page. When you're in Linked In, find your name in the upper right corner of the screen. Click the little arrow which opens a drop down box. Click "Settings." Your join data is listed in the upper left corner of the page.