Consider that updates to commercial software that can be bundled with addware gets tested for bugs and usually provides a patch for vulnerabillities; addware is simply an aplication on your pc displaying adds while you serf the web, some programs force you to install addware to run there program under the assumption that it helps pay for the development and support. It's not necessarilly bad to have addware on your system, as long as it isn't downloaded and installed without your permission, Edonkey for exsample includes addware but also includes an agreement in reguards to it; any addware that installs on your system without your consent or knoweledge has been termed mallware, normally it will display exsessive adds, reset your homepage, access other sites in the background among other things; some of these apps can be verry difficult to remove, I would recommend keeping up to date on the latest high risk threats.