advertising, public relations and marketing  

ads means its your product who have been indorsed or seen in tvs or screen to be known..public relations ..its on dealing with people..and marketing ..its the act of seeling whatever your products have..through the aid of ads..

For some reasons, I think they're all the same thing.

Advertising is when someone pays outright to place an ad or commercial in a magzine, on TV, a Web site, etc.

Public relations is a less obvious practice. PR people try to get favorable coverage in the media for their products or services, without actually paying for the coverage. For example, they'll send a press release to a newspaper, hoping that they'll print it with few or no changes.

Marketing is a broad term for the practices used to market and promote something. Marketing can include PR and advertising, as well as displays in stores, etc.