Slashes in the middle of text?

Weird how a slash sometimes end up in the text, and it isn't for a website. I sometimes struggle with slashes in the text because there are so many ways to interpret their meaning. In a blog guideline it can be used to denote an "either or" for the words being used. In a book that has confined space it sometimes is used for a person singing or reciting a poem. When I write up notes it can be an "either or" thing or a "both" thing, it can even end up as something used to put words with definitions together. My problem: what exactly does each slash mean?
According to TSMGTW the slash is used to "separate lines of poetry and to separate word pairs that present options or opposites." Assuming that this were always true, and none knew the short ways of saying with or without using slashes (w/ or w/o), what would we suppose these to mean? but since this is not the case it must be assumed that for note taking these abbreviations are still usable. For a quick list of its uses, click HERE!!!!!!!!!!!MUAHAHAHA!!!!!!!