diff --git a/revealjs/information-technology/3-companies.md b/revealjs/information-technology/3-companies.md
index 000c10a..362e77b 100644
--- a/revealjs/information-technology/3-companies.md
+++ b/revealjs/information-technology/3-companies.md
@@ -5,7 +5,7 @@ background-image="img/franz/gears.jpg"
 <notes>
  * Franz
  * Für Dich: Ein <em>commercial</em> ist ein TV-Spot, keine Werbeanzeige!
- * talk about it
+ * most companies: advertising
 </notes>
 
 ---
@@ -71,4 +71,18 @@ background-image="img/franz/music.jpg" background-color="white"
 <notes>
  * subscription fee
  * personalized advertising
+ * contracts with musicians/labels
+</notes>
+
+---
+background-image="img/franz/snapchat.jpg"
+
+## Snapchat
+
+<notes>
+ * personalized advertising
+ * based on (among other things):
+   + content of pictures
+   + geo location
+   + connections to friends
 </notes>
diff --git a/revealjs/information-technology/4-end.md b/revealjs/information-technology/4-end.md
index 51248bf..b62b3f2 100644
--- a/revealjs/information-technology/4-end.md
+++ b/revealjs/information-technology/4-end.md
@@ -11,13 +11,19 @@ style="font-size: 24px;"
 
 <hr/>
 
+ * [Google: Privacy Policy](https://policies.google.com/privacy?hl=en&gl=en)
+ * [Instagram: Data Policy](https://help.instagram.com/519522125107875)
+ * [Newsweek: Spotify Stock: The Pros and Cons of the Company Going Public](https://www.newsweek.com/spotify-public-stock-market-nyse-opinion-quora-870148)
+ * [Snap Inc.: Privacy Center](https://www.snap.com/en-US/privacy/privacy-policy/)
+ * [Spotify: Privacy Policy](https://www.spotify.com/en/legal/privacy-policy)
  * [The Verge: WhatsApp to start sharing user data with Facebook](https://www.theverge.com/2016/8/25/12638698/whatsapp-to-start-sharing-user-data-with-facebook)
  * Schneier, Bruce (2016). *Data and Goliath*. First edition. New York: W.W. Norton, p. 152-153
  * Unsplash:
-   [Malcom Lightbody](https://unsplash.com/photos/401OD83Ke6o),
-   [Tim Bennett](https://unsplash.com/photos/OwvRB-M3GwE),
    [Gian Cescon](https://unsplash.com/photos/N0g-deioHO4),
-   [Malte Wingen](https://unsplash.com/photos/PDX_a_82obo)
+   [Malcom Lightbody](https://unsplash.com/photos/401OD83Ke6o),
+   [Malte Wingen](https://unsplash.com/photos/PDX_a_82obo),
+   [Thought Catalog](https://unsplash.com/photos/xVRdDDe6M1A),
+   [Tim Bennett](https://unsplash.com/photos/OwvRB-M3GwE)
 
 <hr/>
 
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