What is it?
sahplugin.dll is part of the Shop at Home Toolbar. When loaded by IE, it will install a toolbar in the top of your Internet Explore web browser. By installing itself, the toolbar has full access to the a loaded web page's HTML content and knowledge of the URL the user is currently viewing; it can also manipuate these depending on the intended function of the toolbar.
Description of sahplugin.dll from the publisher
“ShopAtHome.com is one of the largest websites offering free online coupons, grocery coupons, cash back rewards, free samples, restaurant coupons and contests. The site is unique from other online deal sites because it gives cash back to shoppers for purchases made through ShopAtHome.com. ShopAtHome.com has experienced unbelievable growth year-over-year since it was launched in 1986. Over the past year, its monthly visits have grown from 19 million to over 37 million with no signs of slowing down. ShopAtHome.com was founded in 1986 by husband and wife team Marc and Claudia Braunstein at their home in Denver. ShopAtHome.com started as a company offering a "Catalog of Catalogs," and, through feedback from users and advances in technology, has become the online coupon powerhouse it is today, with more than 50 employees, including an entire team dedicated to scouring the web for coupons and deals.”