It has nothing got to do with the forum at all, these are all cookies stored on your computer, cookies store information about recent web sites you have visited ,that’s why you are seeing all these advertisements, you will especially see all of these adds if you are torrenting illegal music etc,
Aom said he got an advertisement about accounting; did you recently browse such a site?
Here is a valid definition of a cookie: A cookie is a piece of text that a web server can store on a user's hard disk, Cookies allow a Web site to store information on a user's machine and later retrieve it. The pieces of information are stored as name-value pairs.
For example, a Web site might generate a unique ID number for each visitor and store the ID number on each user's machine using a cookie file.
¬ If you use Microsoft's Internet Explorer to browse the Web, you can see all of the cookies that are stored on your machine. The most common place for them to reside is in a directory called c:windowscookies. When you look in that directory on your computer, each file is a text file that contains name-value pairs, and there is one file for each Web site that has placed cookies on your machine.
You can see in the directory that each of these files is a simple, normal text file. You can see which Web site placed the file on your machine by looking at the file name (the information is also stored inside the file). You can open each file by clicking on it and delete it.