I need to take note of existing content and extract everything as my new content without losing the source).
This question could be similar to Ask HN: How do you manage “knowledge” (https://news.ycombinator.com/item?id=16412343), but I'm not searching for a fully integrated system to take notes, manage the calendar and lose focus immediately trying to adapt to a workflow.
I'm searching for something to tag selections with preconfigured labels, comment using simple text/markdown and capable of visualizing the activity and exporting it as text.