MWSBAR.DLL is a dynamically linked library. In simple phrase, it is an essential component of a particular parasite. Most threats depend on such libraries and wouldn't work without them. The MWSBAR.DLL file can be responsible for the dangerous payload a parasite carries, so deleting it will definitely reduce all the security and privacy risks.
The MWSBAR.DLL file is installed and used by adwares
WebSearch Toolbar.B and
WebSearch Toolbar.bho2. It is also related to other parasites such as
LinkGrabber 99 and
My Search Bar. These threats can use MWSBAR.DLL for different purposes, as the file's functionality depends on a particular parasite it belongs to.
Sometimes a presence of MWSBAR.DLL does not indicate that your computer is infected. It can be an essential system file or a file installed by harmless legitimate software and therefore may not pose any threat to your privacy and the system. Although such cases are quite rare, you should thoroughly examine MWSBAR.DLL before completely deleting or leaving it in the system.
Attack of Waledac Worm is schedulled on July 4 
