Summary: Summery is a restatement (your own words)of what your source is all about. Summaries do not carry opinions or evaluations , they are based on descriptions of the main ideas, which are then broken down into supporting points.
Annotated Bibliography: The difference between search engines and library databases would be that google has instant results once you fill in the description of what your looking for, in databases they consist of mostly articles. Searching in library databases you only need 2 to 4 keywords.
Citation: Citing sources makes you (and your research) more credible. If you don't cite your sources, there are consequences like failing your paper or being expelled from the university.