diff --git a/website/web/__init__.py b/website/web/__init__.py
index e21018a..763e275 100644
--- a/website/web/__init__.py
+++ b/website/web/__init__.py
@@ -95,6 +95,22 @@ def asn_details():
     return render_template('asn.html', sources=sources, ranks=ranks, prefix_ips=prefix_ips, asn_descriptions=asn_descriptions, **session)
 
 
+@app.route('/asn_description', methods=['POST'])
+def asn_description():
+    load_session()
+    asn = None
+    if request.form.get('asn'):
+        asn = request.form.get('asn')
+    elif session.get('asn'):
+        asn = session.get('asn')
+    else:
+        to_return = {'error': 'asn required'}
+    if asn:
+        q = Querying()
+        to_return = q.get_asn_descriptions(asn, session.get('all_descriptions'))
+    return Response(json.dumps(to_return), mimetype='application/json')
+
+
 @app.route('/asn_history', methods=['GET', 'POST'])
 def asn_history():
     load_session()
diff --git a/website/web/templates/asn.html b/website/web/templates/asn.html
index 526a219..a352f14 100644
--- a/website/web/templates/asn.html
+++ b/website/web/templates/asn.html
@@ -5,7 +5,9 @@
 {% endblock %}
 
 
-{% block title %}Ranking - {{ asn }}{% endblock %}
+{% block title %}
+    Ranking - {{ asn }}
+{% endblock %}
 
 {% block scripts %}
     {{ super() }}
@@ -16,6 +18,11 @@
 {% block content %}
   <center>
       <h1>Ranking - {{asn}}</h1></br></br>
+      <button data-html="true" type="button" class="btn btn-secondary" data-container="body"
+         data-toggle="popover" data-placement="bottom"
+                               data-content="<center><b>sum</b>(IP * weight of the list) </br><hr><b>sum</b>(IP in the prefix)</center>">
+        <h4>How is this ranking computed?</h4>
+     </button>
   </center>
   {% include ['top_forms.html'] %}
   <table class="table">
diff --git a/website/web/templates/country_asn_map.html b/website/web/templates/country_asn_map.html
index ff59b6b..7b29542 100644
--- a/website/web/templates/country_asn_map.html
+++ b/website/web/templates/country_asn_map.html
@@ -15,6 +15,3 @@
   {% endfor %}
 </table>
 {% endfor %}
-
-
-
diff --git a/website/web/templates/index.html b/website/web/templates/index.html
index e851ae0..2b7a608 100644
--- a/website/web/templates/index.html
+++ b/website/web/templates/index.html
@@ -5,6 +5,11 @@
 {% block content %}
   <center>
     <h1>BGP Ranking</h1></br></br>
+    <button data-html="true" type="button" class="btn btn-secondary" data-container="body"
+        data-toggle="popover" data-placement="bottom"
+                              data-content="<center><b>sum</b>(IP * weight of the list) </br><hr><b>sum</b>(IP announced by the ASN)</center>">
+       <h4>How is this ranking computed?</h4>
+    </button>
   </center>
   {% include ['top_forms.html'] %}
   <table class="table">
diff --git a/website/web/templates/main.html b/website/web/templates/main.html
index 08a0dd8..45a1aa8 100644
--- a/website/web/templates/main.html
+++ b/website/web/templates/main.html
@@ -4,6 +4,11 @@
     {{ super() }}
     <script src='{{ url_for('static', filename='d3.v5.js') }}'></script>
     <script src='{{ url_for('static', filename='bootstrap-select.min.js') }}'></script>
+    <script>
+        $(document).ready(function(){
+            $('[data-toggle="popover"]').popover();
+        });
+    </script>
 {% endblock %}
 
 {% block head %}