changed based on today's call

Signed-off-by: Doug Davis <dug@us.ibm.com>

primer.md

@@ -236,54 +236,6 @@ general, this is true for all CloudEvents attributes as well.
 This section provides additional background and design points related to some of
 the CloudEvent attributes.
 
-### String Values
-
-Some of the CloudEvent attributes are defined to be of type `String`, and
-all data types used by CloudEvent attribute are required to have a
-string-encoding. This makes for an easy serialization to even the most
-basic formats and transports that might only have a string representation of
-attributes.
-
-Even with that model, it may still be possible to use certain
-characters that could be problematic in some cases. The CloudEvents
-specification does not attempt to further restrict the valid characters used
-for attribute values so as to allow for the specification to be used in
-situations where those potentially problematic characters are desired.
-
-However, this should not be interpreted as encouragement for producers to
-push the boundaries of what characters should be used just for the sake of
-edge-testing implementations. CloudEvents is striving to help with
-interoperability while still being flexible enough to be used in unique
-situations. So, CloudEvent producers are encouraged to only use values that
-have the best chance of being properly processed by all possible formats
-and transports that their CloudEvents might be used with.
-
-### URI-reference Values
-
-Attributes of type URI-reference have quite a large set of valid values that
-can be used. For example, it is possible that the `source` attribute could be
-as short as `home` or could be more meaningful, such as
-`http://home.example.com`. The CloudEvents specification allows for a wide
-range of values to allow for it to be used in as any use cases as possible,
-without undue burden on implementations.
-
-As an example, while `home` as a value for `source` would not be a wise
-choice when the CloudEvent is meant to be used in a very public environment,
-it may make perfect sense in a closed system where a full reverse-DNS name
-might be unnecessary. Or perhaps there is a severe size limitation on
-the size of the CloudEvent and shorter URI-references are needed.
-
-These are decisions that CloudEvent producers will need to decide for
-themselves based on their needs and expected usage of their events.
-
-Additionally, the CloudEvents specification does not define a `baseURI`
-to be used along with the URI-reference type attributes. This is because,
-unless otherwise stated, the URI-references are not meant to be normalized
-or used for any other purpose other than comparing its string value against
-some other URI-reference string value for equality. The use of URI-reference,
-instead of just a String, was done to encourage the use of meaningful values
-with a well-defined structure.
-
 ### id
 
 The `id` attribute is meant to be a value that is unique across all events

spec.md

@@ -252,6 +252,7 @@ The following attributes are REQUIRED to be present in all CloudEvents:
 - Constraints:
   - REQUIRED
   - MUST be a non-empty URI-reference
+  - RECOMMENDED that an absolute URI be used
 - Examples
   - Internet-wide unique URI with a DNS authority.
     - https://github.com/cloudevents