The Semantria Ruby SDK by Lexalytics connects to the API to access sentiment analysis, keyword extraction, and word categorization. Semantic web services also include examples that allow users to interact with auto-response and discovery mode.
Our API directory now includes 22 sentiment APIs. The newest is the Bitcoin Sentiment API. The most popular, in terms of mashups, is the Klout API. We list 7 Klout mashups. Below you'll find some more stats from the directory, including the entire list of sentiment APIs.