There is a configuration command (undocumented, as often seems to be true with LJ) that will disable this operation for your own page and for any LJ links you click on. That is described in the additional documents linked to the Slashdot article above.
If this wasn't a deliberate, policy based action by LJ management, then it seems likely to be a clever hack inserted by individuals in the coding team or someone with illicit access to the code base. Given that LJ has no policy statement forbidding such "partnership" links, a unilateral action to disable them seems questionable at best, and to my mind is a violation equal to the privacy violations Google committed a couple of weeks ago in their heated reach to grab market share away from Facebook and Twitter. (The Google Buzz cockup is now well and thoroughly dIscussed elsewhere.)