The Wikifier identifies important entities and concepts in text, disambiguates them and links them to Wikipedia. Wikification is an important step in helping to facilitate Information Access, in knowledge acquisition from text and in helping to inject background knowledge into NLP applications. The main decisions the Wikifier must make are: (1) What expressions to link to Wikipedia. (2) Disambiguating the ambiguous expressions and entities. This Wikification demo uses four types of features: (a) String matching and prevalence of entities in Wikipedia. (b) Lexical similarity between the input document and the Wikipedia pages. (c) "Semantic Similarity" between the ESA summary of the input document and Wikipedia pages. (d) How likely is a set of Wikipedia pages to be linked from a single document (we get this statistic by looking at the linkage patterns in Wikipedia).