With today being Valentine's Day, its an appropriate time to talk about being "on" and "off" the market. In a dating sense, being "On The Market" means you are available; while being "Off The Market" means you are taken.
From a real estate perspective, many agents try to solicit business from potential sellers or buyers by promising to find properties that are "Off The Market".
That said, similar to dating, it's best for property to be listed and marketed by an agent to all prospective buyers to attract the most qualified purchaser.
You only need one, but you need to find the right one...because nobody likes a board rejection!
Happy Valentine's Day!