This forum is largely un-monitored now. If you look to other platforms such as
The source code repository on GitHub - https://github.com/Reactive-Extensions/Rx.NET
The related issues on the GitHub Repo - https://github.com/Reactive-Extensions/Rx.NET/issues
The related gitter chat channel - https://gitter.im/Reactive-Extensions/Rx.NET
The Slack chat channel - http://tattoocoder.com/aspnet-slack-sign-up/
On Stack overflow - http://stackoverflow.com/questions/tagged/system.Reactive
The content on IntroToRx.com is still relevant even though it was written against v1.0.10621.0 of the Rx code base. Changes in Rx2.0 and now more recently Rx3.0 more predominantly additions of features (async await support, .NET core support). The examples
should still compile and work in the latest builds.