Many web sites use bugs to track your online activity, for a variety of purposes. There are hundreds of third party tools and sites that web sites that offer bugs.

Some websites implement tracking in such a way that if you block the tracking (for example with a tool like Ghostery, which has a bug list that now numbers over 475), core functionality can be lost. Whether intentionally or by accident, southwest.com has recently joined the list of "No spy? Goodbye!" web sites.

Symptoms of this problem: top menu bar drop downs do not work; no RT/OW radio buttons on the flight page; city flyouts on the flight search and results pages do not work (which would be a good thing except that the way in which they do not work prevents the kludgy interpretation/copying of your input to the hidden functional part of the form). The input fields on the home page do continue to work, but you lose the ability to change the city inputs from the results page.

The only full solution is to disable bug blocking for southwest.com. Partial solutions are to use the "decrapified" input page, or bookmarkable flight search URLs; you'll still have the issue of not being able to modify your city selections from the results page.

I haven't tested for loss of functionality beyond the search results page. It is possible that southwest.com is now a "No spy? No buy!" web site.

I also don't know whether or not IE9's TPL (tracking protection list) feature will cause loss of functionality.