Press release is very beneficial technique through you can promote your article, video and audios in news sites and high pr dofollow sites. Through press release you will get the back-links and traffic on your site. Basically Press release is used for promote your website through press release sites, news sites etc.
It's good but it's important not to overdo it, Google has recently updated its guidelines on this topic
--- Référencement Suisse et gestion d'image internet, pour le positionnement dans les moteurs de recherche.