What is the Online Version link and why would recipients click on it? Are links to the Online Version Tracked?
Including an Online Version or web version of your email is a best practice that many ESPs provide. Because different email clients, browsers, etc. can render email differently, many ESPs will enable you to create a web-based version of your email, including this link in your email send. That way, if the images or anything else isn't rendering properly for your recipients (or if it is just their preference to see the online version), they can easily click over to the web-based version and see exactly what your marketing team intended.
When users click on the Online Version of your email, all of the clicks that come in from that version are also tracked within your analytics reports. So for example, if you click on the Online Version of your email, and then click on three other hyperlinks from the Online Version, not only will the Online Version click show up but all three clicks to the links you clicked from the Online Version will also register. These clicks also show up on the Clickthrough Heatmap Report.