As a result of Delta and Northwest's merger potential, merger discussions between United Airlines and Continental Airlines have also reportedly "grown more serious," said the article. United has proposed a merger with Continental before and has been turned down, but if Delta and Northwest announce a deal, Continental could change its mind very quickly and agree to merge with United, which has been actively looking for a merger partner for some time now.
An interesting point in all of these merger talks is Northwest's so-called "golden share" in Continental. This is basically some preferred stock that allows Northwest to abort a merger between Continental and another carrier. If Northwest and Delta do merger, however, Continental has the option to acquire the "golden share" for $100. Continental would be able to get the stock even if the Northwest-Delta deal later falls through.
The mergers raise a lot of inevitable questions - what types of aircraft will the combined operations operate (what will happen to Northwest's A330s)? Which hubs will stay open and which will close or be downscaled (