BDSM stands for Bondage and Discipline, Domination and Submission, Sadism and Masochism. Although some like to play in the bedroom and experiment with roleplay or even just find themselves turned on by what may be considered these days as "unconventional" sexual acts, many people live daily lives in these lifestyles unaware of the "fetish" it has become. Domination/submission relationships exist outside the bedroom.
Bondage falls into various ways of binding your partner-- either by themselves, leaving them motionless, or binding them to something. Putting the discipline into bondage creates an atmosphere where the actual need for binds may not be necessary. Your actions, words, and general presence give off a dominating impression. Using the two together brings an entire experience of being under control of someone else and having no control as to what you do. This is something that can be interpreted as life acts for some, although having sexual aspects and pleasure, they transfer into an everyday relationship lifestyle. In that lifestyle, bondage and discipline fall into more of an emotional and physical life effect rather than a roleplay one. Bondage becomes the security of being bound to that person completely, leaving you in their hands. Putting discipline into that ties in the lifestyle with rules and regulations as to how things should go, including punishments when things don't go as they should. Using lists, words, and clear communication on a regular basis leave out the "normal" relationship issues of miscommunication and complications.
In both roleplay and lifestyle, domination and submission work a lot in the same way. As roleplay, people enjoy exploring something they may not normally or merely feel good being in control or out of control in the bedroom. In a lifestyle, domination goes beyond just controlling what your partner does sexually, as submission goes beyond your partner just wanting to be controlled sexually. People who identify as doms or subs, meaning they do not just play in the bedroom, are merely extending their personalities. Having clear defined roles, some have continued to live in those roles as a natural state of who they are.
Falling under having control and giving up control, sadism and masochism are linked to inflicting or taking physical or emotional pain as well as humiliation as a means of sexual release. In roleplay and lifestyle, sadism and masochism serve as forms of attachment between partners where trust is shared. BDSM as a lifestyle uses these acts as a form of unconditional love to your partner, conveying them into everyday life of commitment and constant reassurance that the control is there. This is something that is not just done as a form of sexual release but on a regular basis as a form of control. The pleasure of pain and humiliation goes beyond sexual aspects as the physical and emotional marks become ownership.
When taken literally, BDSM is automatically jumped to as a fetish/kink of naughty proportions. Historically, most people have lived in BDSM relationships without categorizing it as such because it becomes more than just sexual acts. When looked at in the porn industry its categorized as roleplay or undermined by people who use it as a means to make more money having no actual interest in the aspect. We have grown to a time of understanding and it should be understood that BDSM isn't just play to some. It is simply life.