This is not so much a "new feature" as much as a plea to restore an old feature.
In Confluence 5.1 (and earlier?) you used to be able to limit a search to Site Spaces ... i.e. exclude Personal Spaces. (There was also the option to search only Personal Spaces, but this was not nearly as useful.)
Somewhere between Confluence 5.1 and 5.5, Site Spaces was removed as an option.
This was a very important feature because pages in Personal Spaces have a bad habit of bubbling to the top of search results, and they are rarely the desired result. Being able to simply exclude those pages, caused an immediate improvement to the search results.
In fact, I contend it should have been – or been settable as – the default behavior.