- The transaction is not that much anonymous
It's completely anonymous. No third party will know sender and receiver.
This totally depends how well are you "hiding" any link between you as a person and your address. Even if they don't know who you are link can be establish link with what services particular person uses with his address as you can mostly tag which service owns which address and there are tools being developed where you can see via graphs, so in graph representation, how and where are coins moving.