Why I think that the windows-application tag should be deleted:

• It's about Windows software, but this site is for Ubuntu. The only circumstances I could see it relating to Ubuntu would be if the OP wants to run a program under Wine, or if the OP wants to find an Ubuntu alternative to a Windows application. If it's about Wine then the tag is rather redundant since that's all Wine does so using winewindows-application doesn't add anything useful to the question. If it's about finding an Ubuntu alternative to a Windows application then it's a software-recommendation. The Windows part is irrelvant since the question is actually about what the program does, besides tagging a question software-recommendationwindows-application would suggest the OP is looking for a Windows application, which would be off topic.

• There are currently only 5 questions using the windows-application. 4 are about wine so the tag is redundant, and other is about running the Ubuntu One Windows client on Windows. Aside from the fact that Canonical (the makers of Ubuntu) own the Ubuntu One cloud service it has nothing to do with Ubuntu making it off topic. On top of that Ubuntu One is dead. None of these 5 questions are benifitting from the use of the windows-application or providing compelling examples of it's use.