Note that many websites have their own advertising, unrelated to adware.
This adware program is in the form of a toolbar. Normally it will be installed from websites as an active X control. Many sites may have this toolbar installed from their website because they receive $.15 per installation. Often times it will be bundled with Zango and Media Access.
From their website:
"Matcash is an affiliate Toolbar that pays you each time a surfer installs our Toolbar on his computer."