In my humble opinion the 14 year old comment adds a lot to the content.
Let’s take messages for example, a few years back someone maybe implementing their own messages by passing a String, String map to the Twirl template while, someone last year may simply call messages, and someone today may pass the request over to Twirl. In an unofficial unstructured way this is giving the reader who wants to seek more information beyond the guide a perspective of evolution.
Also I am not sure why, but it seems the guide has been rewritten, instead of being updated. This is a problem in and of it self. You have people in the community referencing the old guide because it either has better graphics to illustrate a point or the page is missing all together(Thinking of Authorization here).
I honestly see the discuss forums as a horrible bootleg version of the Stack Over flow forums. The fact that they both use tags to organize topics makes them useless, unless they are being indexed, like Stack Overflow is by Google. They should at least be tied to an official guide.
The idea being that anyone who reads and understands the guide should be familiar enough with the topic in order to answer questions related to the topic.
For example today I have a question regarding Twirl templates. I am not sure where to ask, since twirl is a siloed project that is heavily use by the Play Framework. How can I ask this question so that people who have the same question while reading the guide can access it?
It is related to the topic, but not important enough to be part the guide.