Is it possible to dismiss the notifications that hover over the current window? I've noticed that they become translucent on mouseover (but they still tend to cover part of the current window!). Is it possible to actually close these notifications so that they will be slightly less irritating?
As Lord of Time said, this is not possible at this time....well..sort of.
There is a patched NotifyOSD that will allow you to close them on click and various other customizations.
Selected out-takes from http://www.webupd8.org
There are other options listed but that one pertains specifically to your question.
There is a lot of information on the page I linked to so I will not just copy it all here, but refer you to the page so you can read more about it and decide if it's something you want to do.
You will need to enable a custom PPA repository to install this fix. This fix actually upgrades the
In a terminal window, ctrl+alt+T, enter the command
will do it and any pending notifications get purged too