Note that many websites have their own advertising, unrelated to adware.
Adware is any software application in which advertising is displayed while the program is running. The authors of these applications include additional code that delivers the ads, which can be viewed through pop-up windows or through a bar that appears on a computer screen and sometimes through text links or in integrated search results. Adware may or may not track personal information. It may also gather information anonymously or in aggregate only. Users should check the EULA and Privacy policy to ensure if the adware on their machines conforms to their standards.
Official Description:
Changes Internet Explorer settings and changes the startpage.
pqnelhleyy 365725c4 5399e756
Has ability to download unwanted software. A BHO that's loaded in the users directory like:
C:\Documents and Settings\Jon Doe\Application Data\iefeatsl\