Is there a standard meaning for _csuid/__qsa in cookies?

Is there a standard meaning for _csuid/__qsa in cookies?

I was perusing my cookies, and discovered several cookies from various different sites, which all have the same value. They are all named "_csuid". I have another set, all from different sites, all with the same value, named "__qsa". It seemed rather strange that they would all be identical, despite coming from different sites.