Recall means getting back all the examples in your data which display that factor. You can get high recall by writing a script which returns a lot of results. There is always a second step, to go through the examples yourself as a human to filter out the extraneous examples. Getting high recall is generally a good first step when you start your research (think: google web search, you really want to know all the authors that have written on your topic...)
Precision means getting data that you can run stats on and get statistical significance. High precision means all the results are what you were looking for. Getting high precision is important to make any claims or generalizations, its generally the last step (and highly valued) in your research.