MassMine allows you to easily datamine Twitter, Google, Wikipedia, and soon Facebook for data. Pretty cool! From the official site:
MassMine is a social media mining and archiving application that simplifies the process of collecting and managing large amounts of data across multiple sources. It is designed with the researcher in mind, providing a flexible framework for tackling individualized research needs. MassMine is designed to run both on personal computers and dedicated servers/clusters. MassMine handles credential authorizations, rate limiting, data acquisition & archiving, as well as customized data export and analysis.