I wouldn't say they're explicitly Ubuntu One related.
CouchDB is a database. It's a fairly light, fairly fast way of storing simple data. Applications can use it to store their data. One advantage over things like SQLite (that is faster than CouchDB) is it is much easier to dump a load of records to JSON and import them at another end without conflict. You can do this with relational databases but it usually means layering on some transaction-logging logic which can still cause problems in asynchronous settings. This means it can easily be used in version control systems like Ubuntu One a lot more efficiently.
I think we're getting away from the real point somewhat. The clue that something isn't right should be the presence of
ubuntu-desktop in that lot. It's just a metapackage but it holds the dependencies for most of the Ubuntu desktop system. If you remove it, and then something does an auto-remove, you'll probably lose most of your desktop.
There's also a conflict with
xulrunner-1.9.1 which is a core dependency of Firefox.
libmozjs-dev isn't compatible with whatever you're trying to install it on. I note that
libmozjs-dev has been dropped from the past two releases so if you're trying to force it into Lucid or Maverick (10.04/10.10) I would stop now and look for another way of installing it (namely downloading it from Mozilla and compiling it yourself).