In addition to what others said, there's even fewer differences between them internally. Salsa20 <stream cipher> is not a "traditional" stream cipher -- basic

In addition to what others said, there's even fewer differences between them internally. Salsa20 <stream cipher> is not a "traditional" stream cipher -- basically it's Salsa20 <hash function> (not collision resistant) in counter mode. The hash function itself is implemented as permutation with final addition of input words to make it irreversible. With this permutation you can build a block cipher, and by the way that's what SHA-3 finalist BLAKE does by introducing addition of key words during rounds (except it's built on a variant of Salsa20 called ChaCha20). (I'm not saying that you should build your own block cipher from Salsa20, of course :) The original sentence, though, is: try Salsa20 rather than AES and Poly1305 rather than GCM. AES-GCM is also not a "block cipher".