The similarity analysis component determines the percentage of syntactic similarity between two texts. Syntactic similarity indicates exactly how similar two texts are taking into account the exact wording. Semantic similarity would indicate how similar two texts are in meanin g.
So if you take a text and replace all words with synonyms and restructure sentences, the semantic similarity would be high (the meaning is still the same) but the syntactic similarity would be low (the words are different).
% Of similarity, text clustering based on similarity.
Useful to finding exact duplicates, close duplicates or detecting plagiarism.