@blatham,
I read a great many books, magazines, newspapers, on-line blogs & reference sources and even an occasional dirty pamphlet I keep in my sock drawer. I also listen to my car radio and watch my TV.
As with many people I take all of this information in, assess it, ruminate over it, synthesize it and store it various mental sock drawers.
If I were writing a scholarly book or paper, and not hammering out a response in an internet discussion forum, I would certainly honor traditional scholarship and provide relevant footnotes and a bibliography, but...
Generally speaking, when I address factual issues like the assaults of Wilson & FDR on American liberties I often will confirm or hone my understanding of specific instances by consulting on-line references. As I don't want to spend hours researching any topic for A2K, I rely, perhaps overly so, on Google to point me in the right direction. Frequently that direction leads me to Wikipedia.
When I first discovered Wikipedia, I had an admittedly condescending and skeptical attitude about it. Over the years I came to find my condescension was (as it is 99.99% of the time) unwarranted. Not quite the same with skepticism. While I have found less examples of bias than I first expected, it exists but usually in such a blatant fashion that it's easy to identify (Of course this widely opens the door to the distinct possibility that I have been taken in by more artful applications of bias, but show me any reference source that is totally free of the influence of bias, and life is too short double and triple check every reference for a discussion forum).
The great thing about Google and Wikipedia is that if one finds reason for skepticism about something written in Wikipedia, one need only hit the back button for a list of alternative sources. Of course this, in turn, raises the issue of people shopping for the "facts" they like, but at some point we all form an opinion on the integrity of fellow participants here as well as the extent of their individual myopia. As for the latter, I'm informed in this regard by the sources the individual most often cites. Personally, for this reason, if I find something in National Review or American Conservative that I want to reference in a post, I search for confirmation in sources like the NY Times, Washington Post, New Yorker etc. This serves two purposes: 1) If I can't find at least roughly confirming reports in "alternative" sources, I seriously question the original and 2) I find it more effective to use the NY Times or Atlantic to support my contentions here than FOX or the Weekly Standard - at the very least it eliminates a few responses like "Well of course you'd find that in that Right Wing rag!"
(I once was able to cite "Mother Jones" to support a contention on Frankenfood. That was the A2K equivalent of winning The Masters.

)
I've expressed my understanding of progressivism and my opinion of progressives. When I copy and paste, I try to remember to include attribution and provide relevant links. I'm too conceited to intentionally plagiarize, but if someone thinks I have, they should point it out. It's not a practice that I find to be trivial, even here in a discussion forum.
If you believe that I am partially or completely off the mark in terms of my understanding of either the substance or history of progressivism make yourself clear. You only should provide the scholarship you demand or expect from others.