A CNN/Money Magazine report today says that Lincoln is joining the trend of naming its models with a string of letters instead of a name. It seems that those who drive Town Cars or Navigators identify their vehicles that way, and not as Lincolns. Lincoln wants its brand to be foremost in buyers' minds, hence the change.
What would be really nice would be if they switched to making vehicles that didn't suck. There's little chance of that, though.
Update: CNN Money also has an article on just what the model designations mean (or don't mean).