There are actually many tools that can ease your effort on monitoring tweets. As in this particular case, some tools can help monitor particular keyword, say "system analyst" "designer" in separate columns/views so that you will be able to extract 1st hand information whenever they have new openings with those keywords. Although some may argue that sending resume to employers in the first few days will have lower success rate, if you actually respond to new opening within the first few hours you will definitely have distinct advantage over others :)