It probably is not meant for you.
Careers 2.0 let's you build an online resume, and it also let's prospective employers find you. If you are not currently interested in developing a career in IT, then by all means, just ignore the invite.
Although I have heard of job offers being given to 15 y/o coders before. :-)
Accepting the invite won't do any harm of course, you yourself control the visibility of the CV you create on Careers 2.0. You can keep it private and hidden if you want:
respectively. I believe thse are set to 'private' and 'Block all messages and searches' by default, it's just that my settings are currently wide open.