For an explanation of cookies, IP addresses please see below.
Cookies can sound a bit Orwellian and "Big Brother", but mostly they're pretty harmless and unless you land on a website that requests your data and you offer it, the data they hold is mostly anonymous, they don't have your name and email address etc. You can clear out your cookies by clearing your browser history.
Session cookies are added to your machine as you surf websites. They are only retained for as long as your browser remains open. They allow a form of memory to exist between your browser and the websites you visit, such as pages visited, shopping cart contents, last viewed items etc. These cookies will remain after you leave the website but will be deleted once you close the browser (fully close it, not hide or minimise it).
"Persistent cookies" remain on your computer even after you've closed the browser. 1st Party cookies can only relay information back to the website that placed them on your computer. Typically they're used to store site preferences to save you from having to re-enter information on future visits. They may also be used to track your activities (links clicked, pages visited etc.) while visiting a site. Persistent cookies remain on your computer until you remove them, normally by using the browsers clear history feature, although other methods exist.
"Persistent cookies" remain on your computer even after you've closed the browser. 3rd Party cookies are typically used when a website has part of its content delivered via a third party, like embedded videos, maps etc. Websites featuring advertising commonly use 3rd party cookies to deliver the adverts; Over time 3rd party cookies will build up a profile your online habits (websites viewed, links clicked etc. so they can deliver targeted adds. 3rd party cookies have other purposes too, for more information on this we suggest you search the internet for "what do 3rd party cookies do?". We try to avoid third-party cookies as much as is possible. However, we may, from time to time utilise third party content and cannot guarantee that such content does not have third-party cookies delivered with it. Persistent cookies remain on your computer until you remove them, normally by using the browsers clear history feature, although other methods exist.