I don't wholeheartedly embrace everything in this article -  but they certainly got one thing right. Recruiters no longer need a formal cover letter. You'll be much more effective and approachable with a short note expressing your interest and a resume or link to your online profile. 

Cover letters were made for an age where people typed resumes and cover letters, stuffed them in envelopes and mailed them to companies. In that era people had a shared home phone and weren't likely to answer the first time the recruiter called them. It only makes sense that we dispose of this formality. If you're still using a long formal cover letter, it looks tired. Please retire it.