These ads are paid ads - it means the website's advertising with the search engine in the PPC (pay-per-click) method. It's a form of outbound marketing, which means you advertise your business in mass-advertising methods, such as these paid ads, as well as banners, junk mail, etc. There's also a a form of web marketing called inbound marketing (http://en.wikipedia.org/wiki/Inbound_marketi
ng),
which does the opposite things and lets the target audience find the business itself through useful content links instead of the other way around. It's considered more effective than paid ads. Some web-based companies, like www.servula.com, provide these services.