diff --git a/README.md b/README.md
index 34ad9c2..d59597e 100644
--- a/README.md
+++ b/README.md
@@ -146,7 +146,7 @@ full implementation details.
-### Phase 4 (Open for Proposals)
+## Phase 4 (Open for Proposals)
The following tags should be considered purely as work in progress proposals. They should not be relied upon or implemented except for testing purposes and experimentation.
@@ -208,6 +208,7 @@ Example:
+----
### **\** - [Discuss](https://github.com/Podcastindex-org/podcast-namespace/issues/205)
@@ -249,7 +250,55 @@ Example:
+----
+### **\** - [Discuss](https://github.com/Podcastindex-org/podcast-namespace/issues/263)
+
+
+
+
+
+```xml
+[podcast|music|video|film|audiobook(string)]
+```
+
+
+
+Channel
+
+(optional | single)
+
+This tag tells the an application what the content contained within the feed IS, as opposed to what the content is ABOUT in the case of a category. This allows a podcast app to
+modify it's behavior or UI to give a better experience to the user for this content. For example, if a podcast has `music` an app may choose to
+reset playback speed to 1x and adjust it's EQ settings to be better for music vs. spoken word.
+
+Accepted medium names are curated within a list maintained by the community as new mediums are discovered over time. Newly proposed mediums should require some level of
+justification to be added to this list. One may argue and/or prove use of a new medium even for only one application, should it prove different enough from existing mediums to have meaning.
+
+**This list is currently a non-exhaustive proposal and subject to change**
+
+- `podcast` - Describes a feed for a podcast show.
+ - *Justification*: Nothing new, as this is what all podcasts that exist default to today. If no `medium` tag is present in the channel, this medium is assumed.
+- `music` - A feed of music organized into an "album" with each item a song within the album.
+ - *Justification*: Music has existed as a medium for a very long time and dedicated music applications already exist.
+- `video` - Like a "podcast" but used in a more visual experience
+ - *Justification*: Videos add different enough level of user experience to discern them from regular podcasts. Sites like YouTube already exist and prove out the existence of "videos" as a medium.
+- `film` - Specific types of videos with one item per feed.
+ - *Justification*: While doable, users have come to expect to be able to search for films without directly subscribing to a high level organization of "channels." This allows the application to make beneficial assumptions regarding how to handle an item within a film. Films exist as a medium already with dedicated applications today.
+- `audiobook` - Specific types of audio with one item per feed.
+ - *Justification*: Similar to a film, users typically search for audiobooks by name without some level of subscription/following. This isn't to say that an application couldn't allow following an "author," for example, but that wouldn't be organized at the channel level. Audiobooks exist as a medium already with dedicated applications today.
+
+Example use for a "podcast":
+```xml
+podcast
+```
+
+Example use for "music":
+```xml
+music
+```
+
+
## Other Proposals