If someone knows your, e.g. twitter account, then he would be able you find you in other networks and validate that is it really you. You can list only networks

If someone knows your, e.g. twitter account, then he would be able you find you in other networks and validate that is it really you. You can list only networks where you want to be found (like facebook, twitter, instagram, pinterest, foursquare where you can be found anyway). I do not see any security threat here. Only security gains, if someone creates fake profile of you (could be useful for small companies, etc.)