Index: openacs-4/packages/acs-templating/tcl/head-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-templating/tcl/head-procs.tcl,v
diff -u -r1.17 -r1.18
--- openacs-4/packages/acs-templating/tcl/head-procs.tcl	4 Mar 2010 19:51:34 -0000	1.17
+++ openacs-4/packages/acs-templating/tcl/head-procs.tcl	19 Sep 2010 10:23:50 -0000	1.18
@@ -161,6 +161,47 @@
     ]
 }
 
+ad_proc -public template::head::defaults_meta {
+    {-http_equiv ""}
+    {-name ""}
+    {-scheme ""}
+    {-content ""}
+    {-lang ""}
+} {
+    Add a meta tag to the head section of the document to be returned to the
+    users client if the meta tag does not yet exist.
+    Either name or http_equiv <strong>must</strong> be supplied.
+
+    @param http_equiv the http-equiv attribute of the meta tag, ie. the 
+                      HTTP header which this metadata is equivalent to
+                      eg. 'content-type'
+    @param name       the name attribute of the meta tag, ie. the metadata 
+                      identifier
+    @param scheme     the scheme attribute of the meta tag defining which 
+                      metadata scheme should be used to interpret the metadata, 
+                      eg. 'DC' for Dublin Core (http://dublincore.org/)
+    @param content    the content attribute of the meta tag, ie the metadata
+                      value
+    @param lang       the lang attribute of the meta tag specifying the language 
+                      of its attributes if they differ from the document language
+} {
+    variable ::template::head::metas
+
+    if {$http_equiv eq "" && $name eq ""} {
+        error "You must supply either -http_equiv or -name."
+    }
+    if { ![info exists metas($http_equiv,$name) ] } {
+        set metas($http_equiv,$name) [list \
+        $http_equiv \
+        $name \
+        $scheme \
+        $content \
+        $lang \
+        ]
+    }
+}
+
+
 ad_proc -public template::head::add_style {
     {-style:required}
     {-title ""}
Index: openacs-4/www/blank-master.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/www/blank-master.tcl,v
diff -u -r1.48 -r1.49
--- openacs-4/www/blank-master.tcl	12 Jul 2009 01:12:33 -0000	1.48
+++ openacs-4/www/blank-master.tcl	19 Sep 2010 10:23:50 -0000	1.49
@@ -246,6 +246,19 @@
     }
 }
 
+# OpenGraph protocol http://opengraphprotocol.org for social networking
+# Should these use parameterized values instead? 
+template::head::defaults_meta -name "og:title" -content $doc(title)
+template::head::defaults_meta -name "og:type" -content "website"
+template::head::defaults_meta -name "og:url" -content [ad_return_url -qualified]
+template::head::defaults_meta -name "og:image" -content "[ad_url]/favicon.ico"
+if { [info exists ::template::head::metas(,description)] } {
+    template::head::defaults_meta -name "og:description" -content "[lindex $::template::head::metas(,description) 3]"
+}
+template::head::defaults_meta -name "og:site_name" -content [ad_system_name]
+
+
+
 template::head::prepare_multirows
 set event_handlers [template::get_body_event_handlers]
 # Retrieve headers and footers