I'm constantly being contacted through LinkedIn by recruiters who clearly haven't actually read my profile - they'll say they've read it and then say that they think I'd be perfect for the Senior Developer position they're hiring for, when my profile clearly has me as a student looking for entry -level positions. When I respond, or when they call me, I tell them my actual qualifications and they say that they'll definitely contact me in the future. To date I have not heard from a single one of them again.