Questions specific to BlogAssist.
If you no longer wish to use BlogAssist, or want to update it to a new version, you need to quit the application. Although BlogAssist doesn't show up in the Dock, it is still a normal Mac application. It uses a small system menu on the right-hand-side of the menubar.
The last item in this menu is the Quit BlogAssist command. Choose this, and BlogAssist will quit (optionally with a confirmation).
You can then either trash the BlogAssist application from your Applications folder, or replace it with a newer version.
If you replace it, double-clicking on the new version will add the system menu back again.
The data is stored in the preferences file, in your Preferences folder. In version 1 the operations were stored externally, but that file is no longer used after upgrading to version 2. The location is as follows, where "~" means your home directory:
"~/Library/Preferences/com.dejal.blogassist.plist".
Check out the BlogAssist User Guide; it includes lots of information about the application.