The tradition is that, if you touch a bride on her wedding day, some of her happiness and luck will rub off. In additional, if the bridal couple has invited a guest to share their special day, the gracious couple and host should greet and talk with each guest personally, if only for a moment.
With that as background, it still is up to the couple whether to have a receiving line. Often, the couple find it is easier to do away with the receiving line. Except at very small receptions, it is not. It is difficult to get around to all the tables to visit all guests during the reception. If the bridal couple believes they can mingle with all guests, the receiving line can be eliminated.
"Professional Development Program" Association of Bridal Consultants 2010