Mozilla, the maker of Firefox, has recently announced that it intends to block third party cookies as a default in an upcoming version. You can read all about what third party cookies are and what they mean here. In a nutshell a first party cookie is placed on your computer from the website you are visiting, a third party cookie is placed on your computer by another company that has some sort of content on the webpage you just visited. As an example advertisements on a website will place third party cookies as you are not visiting their network website but you are visiting a webpage that they have an advertisement on.
What Will Happen?
If Mozilla makes the default option in their browser to block third-party cookies then most, assuming few people check their settings in the browser, then it may effect the revenue of small businesses. Why is this? Small businesses typically rely on advertising for their revenue and do not have the resources to sell advertising directly to advertisers. The thought is that larger businesses will be at an advantage as smaller sites will not be able to generate as much revenue if advertising networks cannot target and increase response rates without the third party cookies. I suggest you follow the link above to learn more for yourself and consider signing the petition here.