Sample script that searches Active Directory for all the contacts created on October 1, 2007 or later. The contact objectCategory is replicated to the Global Catalog. This means you can connect to a Global Catalog server and search across the forest for all contacts.

PowerShell
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$strFilter = "(&(objectClass=Contact)(whenCreated>=20071001000000.0Z))"

$objDomain = New-Object System.DirectoryServices.DirectoryEntry

$objSearcher = New-Object System.DirectoryServices.DirectorySearcher
$objSearcher.SearchRoot = $objDomain
$objSearcher.PageSize = 1000
$objSearcher.Filter = $strFilter

$colProplist = "name"
foreach ($i in $colPropList){$objSearcher.PropertiesToLoad.Add($i)}

$colResults = $objSearcher.FindAll()

foreach ($objResult in $colResults)
    {$objItem = $objResult.Properties; $objItem.name}