This is a Windows system installed file with Windows File Protection (WFP) enabled.
There are 64 versions of webcheck.dll in the wild, the latest version being 9.00.8112.16443 (WIN7_IE9_GDR.120227-1545). The average file size is about 300.42 KB. Some variations of the file have been seen to be installed with the program Windows Internet Explorer 8 from Microsoft Corporation.
The Internet Explorer Web Site Monitor manages subscriptions and is part of the Information Delivery API. Windows Internet Explorer 7 and later. Web Site Monitor is now obsolete, but should not be removed.
(Note, the programs listed below are for all versions of Windows® Internet Explorer.)
(Note, the behaviors below are for all versions of webcheck.dll, select a unique version for details.)
Located in the registry at 'SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Approved'
United States installs about 35.75% of Windows® Internet Explorer.