way to annotate text not in a pdf

Many mac word processors, since the days of FullWrite, have offered the ability to make marginal notes in a text. DTPro isn’t a word processor, but surely we all feel the need to annotate texts we have collected for research and reference, as well as things we write ourselves.

By this I mean a note that appears linked somehow to the text to which it refers. It may be in the margin, it may appear when the cursor hovers over a symbol indicating the presence of a note, or it could even be a classic foot of the page footnote. Any or all of those would get the job done. The older i get, the more important visual juxtaposition is. I can’t rely on my memory to remind me to consult the “comments” file, or to tell me what exactly I was referring to if I make a separate file that says “Smith’s argument about XYZ fails to consider the implications of ABC”. It is SO much easier to have the thought right next to, or connected to, the passage that roused it.

Is there any way such a feature can be added feasibly to DTPro?

As DEVONthink is currently only using standard file formats like plain text, RTF or HTML, this isn’t trivial. However, there’s already a template (see Data > New From Template > Annotation) to annotate any document. Both the document and the annotation link to each other.

…Which works in most cases, but not if the document you’re annotating has been downloaded from the internet, or is an email message - in those cases the link to the annotation doesn’t appear, since the web or mail URL appears in that spot instead.
See this thread too:
viewtopic.php?f=5&t=11053