diff --git a/app/javascript/mastodon/components/status_list.js b/app/javascript/mastodon/components/status_list.js
index 87a95fd12..b82c63a84 100644
--- a/app/javascript/mastodon/components/status_list.js
+++ b/app/javascript/mastodon/components/status_list.js
@@ -26,6 +26,12 @@ class StatusList extends ImmutablePureComponent {
     trackScroll: true,
   };
 
+  state = {
+    isIntersecting: [{ }],
+  }
+
+  statusRefQueue = []
+
   handleScroll = (e) => {
     const { scrollTop, scrollHeight, clientHeight } = e.target;
     const offset = scrollHeight - scrollTop - clientHeight;
@@ -42,6 +48,7 @@ class StatusList extends ImmutablePureComponent {
 
   componentDidMount () {
     this.attachScrollListener();
+    this.attachIntersectionObserver();
   }
 
   componentDidUpdate (prevProps) {
@@ -52,6 +59,39 @@ class StatusList extends ImmutablePureComponent {
 
   componentWillUnmount () {
     this.detachScrollListener();
+    this.detachIntersectionObserver();
+  }
+
+  attachIntersectionObserver () {
+    const onIntersection = (entries) => {
+      this.setState(state => {
+        const isIntersecting = { };
+
+        entries.forEach(entry => {
+          const statusId = entry.target.getAttribute('data-id');
+
+          state.isIntersecting[0][statusId] = entry.isIntersecting;
+        });
+
+        return { isIntersecting: [state.isIntersecting[0]] };
+      });
+    };
+
+    const options = {
+      root: this.node,
+      rootMargin: '300% 0px',
+    };
+
+    this.intersectionObserver = new IntersectionObserver(onIntersection, options);
+
+    if (this.statusRefQueue.length) {
+      this.statusRefQueue.forEach(node => this.intersectionObserver.observe(node));
+      this.statusRefQueue = [];
+    }
+  }
+
+  detachIntersectionObserver () {
+    this.intersectionObserver.disconnect();
   }
 
   attachScrollListener () {
@@ -66,6 +106,15 @@ class StatusList extends ImmutablePureComponent {
     this.node = c;
   }
 
+  handleStatusRef = (node) => {
+    if (node && this.intersectionObserver) {
+      const statusId = node.getAttribute('data-id');
+      this.intersectionObserver.observe(node);
+    } else {
+      this.statusRefQueue.push(node);
+    }
+  }
+
   handleLoadMore = (e) => {
     e.preventDefault();
     this.props.onScrollToBottom();
@@ -73,10 +122,11 @@ class StatusList extends ImmutablePureComponent {
 
   render () {
     const { statusIds, onScrollToBottom, scrollKey, shouldUpdateScroll, isLoading, isUnread, hasMore, prepend, emptyMessage } = this.props;
+    const isIntersecting = this.state.isIntersecting[0];
 
-    let loadMore       = '';
-    let scrollableArea = '';
-    let unread         = '';
+    let loadMore       = null;
+    let scrollableArea = null;
+    let unread         = null;
 
     if (!isLoading && statusIds.size > 0 && hasMore) {
       loadMore = 
;
@@ -95,7 +145,7 @@ class StatusList extends ImmutablePureComponent {
             {prepend}
 
             {statusIds.map((statusId) => {
-              return 
;
+              return 
;
             })}
 
             {loadMore}
diff --git a/app/javascript/mastodon/extra_polyfills.js b/app/javascript/mastodon/extra_polyfills.js
new file mode 100644
index 000000000..546b693b1
--- /dev/null
+++ b/app/javascript/mastodon/extra_polyfills.js
@@ -0,0 +1,2 @@
+import 'intersection-observer';
+import 'requestidlecallback';
diff --git a/app/javascript/packs/application.js b/app/javascript/packs/application.js
index ca6b476e1..01c28e768 100644
--- a/app/javascript/packs/application.js
+++ b/app/javascript/packs/application.js
@@ -1,9 +1,30 @@
 import main from '../mastodon/main';
 
-if (!window.Intl || !Object.assign || !Number.isNaN ||
-    !window.Symbol || !Array.prototype.includes) {
-  // load polyfills dynamically
-  import('../mastodon/polyfills').then(main).catch(e => {
+const needsBasePolyfills = !(
+  window.Intl &&
+  Object.assign &&
+  Number.isNaN &&
+  window.Symbol &&
+  Array.prototype.includes
+);
+
+const needsExtraPolyfills = !(
+  window.IntersectionObserver &&
+  window.requestIdleCallback
+);
+
+// Latest version of Firefox and Safari do not have IntersectionObserver.
+// Edge does not have requestIdleCallback.
+// This avoids shipping them all the polyfills.
+if (needsBasePolyfills) {
+  Promise.all([
+    import('../mastodon/base_polyfills'),
+    import('../mastodon/extra_polyfills'),
+  ]).then(main).catch(e => {
+    console.error(e); // eslint-disable-line no-console
+  });
+} else if (needsExtraPolyfills) {
+  import('../mastodon/extra_polyfills').then(main).catch(e => {
     console.error(e); // eslint-disable-line no-console
   });
 } else {
diff --git a/app/javascript/styles/components.scss b/app/javascript/styles/components.scss
index 880459761..3971a85bc 100644
--- a/app/javascript/styles/components.scss
+++ b/app/javascript/styles/components.scss
@@ -554,6 +554,14 @@
   border-bottom: 1px solid lighten($ui-base-color, 8%);
   cursor: default;
 
+  @keyframes fade {
+    0% { opacity: 0; }
+    100% { opacity: 1; }
+  }
+
+  opacity: 1;
+  animation: fade 0.3s linear;
+
   &.status-direct {
     background: lighten($ui-base-color, 8%);
 
diff --git a/package.json b/package.json
index 993570ce0..995ad6094 100644
--- a/package.json
+++ b/package.json
@@ -55,6 +55,7 @@
     "glob": "^7.1.1",
     "http-link-header": "^0.8.0",
     "immutable": "^3.8.1",
+    "intersection-observer": "^0.2.1",
     "intl": "^1.2.5",
     "is-nan": "^1.2.1",
     "js-yaml": "^3.8.3",
@@ -92,6 +93,7 @@
     "redux": "^3.6.0",
     "redux-immutable": "^3.1.0",
     "redux-thunk": "^2.2.0",
+    "requestidlecallback": "^0.3.0",
     "reselect": "^2.5.4",
     "rimraf": "^2.6.1",
     "sass-loader": "^6.0.3",
diff --git a/yarn.lock b/yarn.lock
index 3c19450b6..e84c045da 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3341,6 +3341,10 @@ interpret@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/interpret/-/interpret-1.0.1.tgz#d579fb7f693b858004947af39fa0db49f795602c"
 
+intersection-observer@^0.2.1:
+  version "0.2.1"
+  resolved "https://registry.yarnpkg.com/intersection-observer/-/intersection-observer-0.2.1.tgz#cb55175f4eebef6436d957a7d1774d39a9248e5e"
+
 intl:
   version "1.2.5"
   resolved "https://registry.yarnpkg.com/intl/-/intl-1.2.5.tgz#82244a2190c4e419f8371f5aa34daa3420e2abde"
@@ -5832,6 +5836,10 @@ request@2, request@2.x, request@^2.74.0, request@^2.79.0:
     tunnel-agent "~0.4.1"
     uuid "^3.0.0"
 
+requestidlecallback@^0.3.0:
+  version "0.3.0"
+  resolved "https://registry.yarnpkg.com/requestidlecallback/-/requestidlecallback-0.3.0.tgz#6fb74e0733f90df3faa4838f9f6a2a5f9b742ac5"
+
 require-directory@^2.1.1:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/require-directory/-/require-directory-2.1.1.tgz#8c64ad5fd30dab1c976e2344ffe7f792a6a6df42"