I'm the lead developer of Twixl Publisher (one of the competitors of Adobe DPS) and I was a bit suprised to see that Adobe chose ".article" as the file extension for the content.
We have been using this extension for our article-based workflow which we introduced in Twixl Publisher 3.5 (released in June 2014).
Since our solution is based on Adobe InDesign as well, this will get very confusing for both your and our customers as there is no way to differentiate between an Adobe Publish .article file and one from Twixl Publisher.
Since our solution automatically registers itself as the default application for .article files, all the article from both Adobe DPS and Twixl Publisher will automatically open up in our app...
We would appreciate if you would consider changing this to something different to avoid any confusion.