If something is ubiquitous, it seems to be everywhere at once — you find it wherever you go, so you stop even noticing it. It is a formal, rather bookish word, but people do use it in a light, joking way: 'the ubiquitous smartphone', 'her ubiquitous black hat'. That joking use is worth watching, because it often carries a small complaint or a smile: the thing turns up so often that it has become a bit much. Strictly, 'ubiquitous' should mean present in every place, but in real use it usually means only 'very common, seen everywhere you look' — nobody thinks 7-Eleven is literally in every single spot in Taipei when they call it ubiquitous. It describes things, not people, most of the time; when it does describe a person, it is a joke about someone who shows up at every event. Grammar note: it goes before a noun or after 'be' ('Coffee shops are ubiquitous here'), and it has no comparative in careful writing — 'more ubiquitous' is common in speech but sounds odd to some readers, since everywhere is already everywhere. The noun is 'ubiquity' and the adverb is 'ubiquitously'.