It can show ambition and enthusiasm, as well as set you apart from other candidates who do not bother to follow up. (exclusive-executive-resumes.com)
Showing genuine interest can help you in differentiating from other candidates; thus, it's important to tailor your letter so it relates to each job application. (jobcluster.com)
Always maintain a professional tone, but sharing a fact or two about why you are a fan of a company could set you apart from other candidates who stuck to the script. (myperfectcoverletter.com)