People hate it, but there are some really good recruiters on linkedin. With some digging, you can find out what recruting firm a company is using. You also have to weed out the junior recruiters trying to connect with everyone on there. Having contacts with a few good recruiters can really go a long way. How to identify? Usually, they will message you with a specific oppurtunity, and will respond with the actually job req when quiried. Caveate is; I say this as someone with a lot of years of experience, so someone who's entry level or green may not be targets of these people.