This document summarizes an overview talk on software similarity. It introduces the speaker and their research focus on malware detection and vulnerability detection. It then provides an overview of the core topics of software similarity, how it is approached in academia, and introduces a new web service that identifies software similarity. It discusses how software similarity can be used for malware detection, software theft detection, plagiarism detection, and software clone detection. It also provides taxonomy of different program features that can be analyzed and examples of how features like ASTs and control flow can be represented. Finally, it introduces resources like a wiki, book, and new web service called Simseer for software similarity.