Urs, thank you for your message - it was already forwarded to the department in charge.
For now, our entire ad system is being revised.
If you see such types of ads, please attach a screenshot and make sure you also provide us with the link to the site, OS and browser. Also, if you have any other suggestions, don't hesitate to write them down - your feedback is highly appreciated.
Great news that you are reworking the advertisement system.
Maybe you and the rest of the uCoz team can look into this solution ( my suggestion ) for a new ad system : http://forum.ucoz.ru/forum/30-88826-1296958-16-1483967739
I will try to check again on mobile phones some free uCoz sites to see how they behave.
Thank you for sending it to the department in charge.