Send a Thank You After Interviewing

There is really no  "downside" for sending a thank you note after a job interview, although most job candidates don't bother to do it. Sending a thank you --if done reasonably well-- will not hurt your chances at a job.

Worst case, your thank you will be ignored.

Best case, it will improve the impression you left after the interview, making you stand out from your competitors..

For a good discussion on 'Thank Yous'  see the article here

Interview Thank You Letters

It may be one of the most commonly dispensed pieces of job-search advice, but sending a thank you note after an interview really is crucial to sealing the deal. Thanking the hiring manager for their time isn't just polite — it also demonstrates a sincere interest in the position and the company. 

According to a survey, 75 percent of interviewers said that receiving a thank you letter from a candidate affects their decision-making process. 

Beyond showing your enthusiasm for the position, a thank you note also allows you to reiterate why you are the best person for the job. See more pointers here.