--- a/browser/extensions/activity-stream/install.rdf.in
+++ b/browser/extensions/activity-stream/install.rdf.in
@@ -3,17 +3,17 @@
 #filter substitution
 
 <RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:em="http://www.mozilla.org/2004/em-rdf#">
   <Description about="urn:mozilla:install-manifest">
     <em:id>activity-stream@mozilla.org</em:id>
     <em:type>2</em:type>
     <em:bootstrap>true</em:bootstrap>
     <em:unpack>false</em:unpack>
-    <em:version>2018.04.17.1338-bb34232e</em:version>
+    <em:version>2018.04.18.1109-e897108a</em:version>
     <em:name>Activity Stream</em:name>
     <em:description>A rich visual history feed and a reimagined home page make it easier than ever to find exactly what you're looking for in Firefox.</em:description>
     <em:multiprocessCompatible>true</em:multiprocessCompatible>
 
     <em:targetApplication>
       <Description>
         <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
         <em:minVersion>@MOZ_APP_VERSION@</em:minVersion>

--- a/browser/extensions/activity-stream/lib/ActivityStream.jsm
+++ b/browser/extensions/activity-stream/lib/ActivityStream.jsm
@@ -34,16 +34,22 @@ const DEFAULT_SITES = new Map([
   ["DE", "https://www.youtube.com/,https://www.facebook.com/,https://www.amazon.de/,https://www.ebay.de/,https://www.wikipedia.org/,https://www.reddit.com/"],
   ["PL", "https://www.youtube.com/,https://www.facebook.com/,https://allegro.pl/,https://www.wikipedia.org/,https://www.olx.pl/,https://www.wykop.pl/"],
   ["RU", "https://vk.com/,https://www.youtube.com/,https://ok.ru/,https://www.avito.ru/,https://www.aliexpress.com/,https://www.wikipedia.org/"],
   ["GB", "https://www.youtube.com/,https://www.facebook.com/,https://www.reddit.com/,https://www.amazon.co.uk/,https://www.bbc.co.uk/,https://www.ebay.co.uk/"],
   ["FR", "https://www.youtube.com/,https://www.facebook.com/,https://www.wikipedia.org/,https://www.amazon.fr/,https://www.leboncoin.fr/,https://twitter.com/"]
 ]);
 const GEO_PREF = "browser.search.region";
 const REASON_ADDON_UNINSTALL = 6;
+const SPOCS_GEOS = ["US"];
+
+// Determine if spocs should be shown for a geo/locale
+function showSpocs({geo}) {
+  return SPOCS_GEOS.includes(geo);
+}
 
 // Configure default Activity Stream prefs with a plain `value` or a `getValue`
 // that computes a value. A `value_local_dev` is used for development defaults.
 const PREFS_CONFIG = new Map([
   ["default.sites", {
     title: "Comma-separated list of default top sites to fill in behind visited sites",
     getValue: ({geo}) => DEFAULT_SITES.get(DEFAULT_SITES.has(geo) ? geo : "")
   }],
@@ -53,22 +59,22 @@ const PREFS_CONFIG = new Map([
     getValue: args => JSON.stringify({
       api_key_pref: "extensions.pocket.oAuthConsumerKey",
       // Use the opposite value as what default value the feed would have used
       hidden: !PREFS_CONFIG.get("feeds.section.topstories").getValue(args),
       provider_description: "pocket_description",
       provider_icon: "pocket",
       provider_name: "Pocket",
       read_more_endpoint: "https://getpocket.com/explore/trending?src=fx_new_tab",
-      stories_endpoint: `https://getpocket.cdn.mozilla.net/v3/firefox/global-recs?version=3&consumer_key=$apiKey&locale_lang=${args.locale}`,
+      stories_endpoint: `https://getpocket.cdn.mozilla.net/v3/firefox/global-recs?version=3&consumer_key=$apiKey&locale_lang=${args.locale}&feed_variant=${showSpocs(args) ? "default_spocs_on" : "default_spocs_off"}`,
       stories_referrer: "https://getpocket.com/recommendations",
       privacy_notice_link: "https://www.mozilla.org/privacy/firefox/#suggest-relevant-content",
       disclaimer_link: "https://getpocket.com/firefox/new_tab_learn_more",
       topics_endpoint: `https://getpocket.cdn.mozilla.net/v3/firefox/trending-topics?version=2&consumer_key=$apiKey&locale_lang=${args.locale}`,
-      show_spocs: false,
+      show_spocs: showSpocs(args),
       personalized: true
     })
   }],
   ["showSponsored", {
     title: "Show sponsored cards in spoc experiment (show_spocs in topstories.options has to be set to true as well)",
     value: true
   }],
   ["filterAdult", {