The line comes from Boris Becker's famous advertising campaign for AOL Germany, which ran in 1999 when the internet was still new to most households. In the television spots Becker asked 'Bin ich schon drin?' ('Am I already in?'), a question about his dial-up connection that became one of Germany's most quoted advertising slogans. 'Ich bin drin' grew out of that catchphrase as its natural punchline answer. Decades later the phrase still circulates in German meme culture, used whenever someone wants to announce their arrival online with a nostalgic nod.