It is very common in the UK for recruitment agencies to advertise fake jobs to build up their databases of CVs.
I've been on both sides of this, as a candidate and looking for candidates. As a candidate been told that job is filled but we will keep your CV on file. Agencies make claims like having "2,000 Java programmers in (my area)". When recruiting for work, I've been sent my own CV from years before.
In both cases, find an agency that can be trusted and build a real relationship with them. If you can trust them from one side, they can be trusted from the flipside.