What is it?
Description of smartbar.gui.mainclient.dll from the publisher
“The most popular and respected Windows Live™ Messenger extension, Messenger Plus! has been downloaded by tens of millions of users worldwide, letting users get more from their Instant Messenger experience including plugins, skins, scripts, sounds, emoticons, and more. Messenger Plus! users benefit from tons of exciting features of this freeware that has been enhancing Windows Live™ Messenger since 2001. Messenger Plus! became a market.com brand in July, 2011. Market.com brings together the best in ecommerce, epayments and emarketing solutions, providing all the needed services for a successful ebusiness.”