Those ads are generated from your browsing history. You see Xojo ads because you are interested in Xojo and may want to purchase it. Unfortunately its marketing dollars lost because you are already a customer.
I don’t block ads. If a site uses them too much then I just leave the site and don’t return. Ads are a viable financial model when the site owner is responsible with them.
@Philip Zedalis is right, you must have taken a certain set of actions on our website that triggered an ad. You don’t start seeing ads by just visiting our home page.