The similarity is that both manage to make the reader connect with the text through a different stimulus.
EXPLANATION↴
Both Text-to-self and Text-to-text are forms of text connection, which launch different stimuli on the reader making him connect and have a certain attachment to the established text. Text-to-self imposes this connection through personal memories that the text stimulates the reader, while text-to-test makes connections between the reader and a text that he has previously read.
