This paper discusses boundaries, relevant theoretical viewpoints, and data gathering methods (especially the development of combined quantitave and qualitative ones) of linguistic landscape studies (LLs), or research into public space signage, covering (non-)commercial and official signs. Recurring themes in LLs are global English, minority languages, language policy, names, and education. LLs is heavily influenced by technological innovations (digital cameras, photo sharing websites etc.), though the human eye cannot be missed in the categorization and interpretation process. LLs' inherent variety and heterogeneity may call the core notion of language per se into question or bring about innovate ideas as to multilingualism, language policy, minority languages, literacy and pragmatics.