It's SOVRN/Viglink affiliate links. They track clicks on links to places like
Amazon and
eBay, and if you actually buy something after linking over there, OldMiniBikes makes a bit of money.
I have the same on DO THE TON. There is an option to allow Viglink to change certain keywords like '
bike' into links to other products/services. You click on those links, and OldMiniBikes makes a bit of money. I don't have that option turned on - I find it a little intrusive. The affiliate link tracking is invisible to the user.
It's how the internet is paid for - any site you see posting links to
Amazon is wrapping them up in affiliate link code to get paid.