The first two shareholder lawsuits were filed Tuesday in federal court in Chicago after the markets closed, seeking class-action status for people who bought stock before the company restated fourth-quarter financial results on Friday. Perhaps those people should have been reading Hacker News: http://www.hnsearch.com/search#request/all&q=groupon&... (The first post is rather long and fairly neutral, but check out…
http://www.hnsearch.com/search#request/submissions&q=gro...
There are articles with headlines like "Industry-Changing, Profit Machine", "Is Groupon The Next Google?" (money quote from the article: "I think that, if anything, Groupon is severely undervalued.", etc. Prize for the first seriously skeptical piece discussed on HN is "Why Groupon is Overvalued" by Phil Michaelson: