It is possible to stop distributing your work under a creative commons license, however that does not revoke the license from anybody who already accepted the license. It does also not stop them from redistributing the work under the same license. See Article 7(b) of CC-SA-BY 3.0:
b. Subject to the above terms and conditions, the license granted here is perpetual (for the duration of the applicable copyright in the Work). Notwithstanding the above, Licensor reserves the right to release the Work under different license terms or to stop distributing the Work at any time; provided, however that any such election will not serve to withdraw this License (or any other license that has been, or is required to be, granted under the terms of this License), and this License will continue in full force and effect unless terminated as stated above.
The license will be terminated when any of the license conditions is breached. One of the conditions is attribution. So if you did supply your name (full name, pseudonym, or user name), and it has been removed by someone else, the license has automatically been terminated for that website. Note that attribution can be done in different ways, for example wikipedia uses the history pages for attribution, that is fine. See Article 7(a) of CC-SA-BY 3.0:
a. This License and the rights granted hereunder will terminate automatically upon any breach by You of the terms of this License. Individuals or entities who have received Adaptations or Collections from You under this License, however, will not have their licenses terminated provided such individuals or entities remain in full compliance with those licenses. Sections 1, 2, 5, 6, 7, and 8 will survive any termination of this License.