From the NYT comes the news that Merck flacks were the real authors of "dozens of research studies" on Vioxx that were then shopped around to name-brand physicians. (WaPo reports as well, here.) Presumably, docs who agreed received some kind of compensation--even if it was just another publication, which is the currency of academic science--for adding their names to the papers and submitting them to journals for peer review and publication. You can read the source article from the Journal of the American Medical Association here.
What's the big deal? Well, for starters, there's the potential for conflict of interest when a drug manufacturer (or anyone else) writes up positive research results about a product in which they have a financial interest. Disclosing such interests is the usual "solution." In this case, there wasn't just non-disclosure; rather, there seem to have been purposeful steps to make it appear as though Merck wasn't involved. Moreover, from the standpoint of research ethics, it's not kosher for people to attach their names to papers they had no role in writing, or research they weren't involved in.
The news also raises the question of whether the research results reported are, in fact, valid and trustworthy. Journal articles are the primary way the medical community learns about advances in clinical care. If people or corporations are willfully putting bad information into the system, patients could suffer or be harmed as a result. The sketchy track record of Vioxx, combined with the news that at least some of the studies that encouraged its adoption in clinical practice might have been written by its manufacturer .... well, it doesn't look good for Merck.