Online Garbage Compaction is back for AEM 6.3. We share a couple of notes about it in this article. Make sure you still are doing Offline Compaction though. Online Compaction is not a silver bullet yet. http://aempodcast.com/2017/infrastucture/online-compaction-aem-6-3/

Both JCR API and the Sling Resource API can be used in AEM.  But which is best?  Here is a breakdown of the performance of both the JCR API and the Sling Resource API using simple test cases as well as a more complex business case: http://aempodcast.com/2017/apache-sling/sling-resource-api-vs-jcr-ap...

Tags are an incredibly useful tool in AEM. I wrote an article explaining some of the ways that you could use them in an AEM implementation for AEM Podcast: http://aempodcast.com/2017/aem-tag-manager/versatile-aem-tag/#.WUAN9xMrLUI.  If you have other examples of how to use tags, then let me know.