I often find that instead of featured questions, in their place are adverts such as this one:
But is it safe to click on these adverts? Do they only advertise stuff on the SE sites? Or is there some special way to apply for this advertising space which means that all adverts and sites they link to are checked to make sure that they are authentic and safe? For instance the Pipelight advert, I want to know more about Piplight, but dare I click the advert? I can't even see where it redirects to.