Set a reference for Microsoft XML.

DIM X As MSXML.XMLHTTPRequest
Dim sURL As String
Dim strResults As String

The rest of your existing code  is rather similar, though I would pass
the variable (SSN) during the initial request, For example...

Set X = New MSXML.XMLHTTPRequest
sURL =
"www.overstock.com/.../d2.cgi
N=0&keywords=" & sSocial
Call X.Open("GET", sURL, True)
X.Send (Null)
strResults = X.responseText

Set X = Nothing