The SE legal link says that using SE constitutes an agreement to certain terms. Section 3 on subscriber content states that "all Subscriber Content that You contribute to the Network is perpetually and irrevocably licensed to Stack Exchange under the Creative Commons Attribution Share Alike license" (I linked the actual code, saving a click). There is also a merger clause
Since The Agreement says that content is perpetually and irrevocably licensed to Stack Exchange under the Creative Commons Attribution Share Alike license, it isn't clear whether the merger clause means "thus excluding any conditions which are not directly stated here", or does it mean "including those specifically contained in the Creative Commons Attribution Share Alike license". My understanding is that a merger clause is a way of disavowing terms that might have come out in previous negotiations, and saying that this is a CC license with a link to said license is like having an appendix (it is part of the contract).
It matters because the requirements of the two licenses are different: the SE license eliminates a number of CC restrictions, such as the self-perpetuating language, and the no-change language (you can't re-write the CC license, you can further restrict use of the material). However, it also imposes a restriction, the link-to-profile restriction, which is not part of the CC license, and dysfunctionally restricts which URI is to be provided by way of attribution, if material is taken from an answer (SE requires a link to the question, not the quoted answer but the CC license allows a choice). How is one supposed to interpret the union of these two licenses?