Hmm... I am somewhat derailing my own topic here (although at least the title does say «и другие слова»), but does «в сети» mean the same as «в онлайне»?
i just heard some people say "Ты в онлайне?" in quick conversations, but it's very, very colloquial, it's kind of accommodating the word to Russian. "Ты в интернете" is the most common way. "в сети" is the same, but i think "в интернете" is mostly used.