This Campingite website (eBible Fellowship) was one of the most extreme. They've completely overhauled their website this past week, deleting much of the May 21st propaganda (Here's a version of the site from last year).
From following some rabbit trail links, I think I came across a statement from one of their key people. Notice, May 21 was a success:
Now, FR did teach through the air additional information, and occasionally during media interviews additional details were offered (concerning earthquakes, etc.); but overall, the message that covered the globe was Judgment Day! It was mostly this that was on shirts, hats, and signs. And indeed, on May 21 that is what took place. None of us need hang our heads because of this. This was of the will of God. Only He could have opened up such a great door and effectual. Overall, the message that got out there was correct. We did err in some of the details as to how this would play out (physically compared to spiritually).May the Lord's perfect will be done, Chris
By the way, a pro-Camping message group can be found here.