Hey Github/Google why don't you add a forum/questions feature just like other "wiki" and "issues" features. Today there is no way project adopters can ask direct questions to the project community without creating an issue and this will not scale, simply because many non-contributors do not read issues and answer's them. So eventually we are keeping big knowledge base out of helping others adopt or solve problems.
Lack of this feature simply discourages people asking questions fearing they are spamming the project with issues, and eventually they will end-up not using the product. And on the other hand if you add this feature it will simply create more value, increase user engagement, and addition of new knowledge base to your system.
You might also argue that why we need to duplicate this feature when there are other good sites like StackOverFlow for doing this, but adding or integrating this feature to your products is more natural as users will find it easy to ask questions being in the right context and these questions have higher chance of being discovered and answered very fast by the whole community compare to other places.
If creating a complete system is going to take a lot of time please consider integrating/buying existing solution like StackOverFlow etc.