Currently you can't subscribe to a member or a tag. This will hopefully be changing later this summer. For RAH your best bet is just to click on the link at the top of the Blu-ray forum, or under reviews on the menu bar.
OK we have put all of the Few Words About threads into the main Blu-ray forum. If you want to filter on the most recent ones there is a link at the top of the Blu-ray forum and one under the review links on the menu bar. Here is the link.
Actually you can't currently follow a member. We are working on some ways to make it easier to keep tabs on the latest "A Few Words" columns and should have an update for you by Monday.