I think adviva and others are cookies.
Cookies are downloaded when you visit a web site, and SOME cookies are used to track what web sites you visit and what you search for (called tracking cookies). This can be used to target the advertising you see on web sites (like this one).
You can set your browser to download no cookies, or you can set your browser to ask you before it downloads any cookies, but the trouble is that some cookies are useful (like the ones that remember your userid and password to help you log on to a web site quickly).
So I would continue to let cookies be downloaded, but make sure you "clear out" unwanted cookies on a regular basis.