I see 情弱乙 being used (as an interjection?) on many websites, but I can't find it in any dictionary, even online dictionaries. I guess the pronunciation is じょうじゃくおつ. What does it mean?
情弱乙！ ガラケーｗｗｗ情弱乙ｗｗｗ 情弱乙と呼ばれないために
It is an internet slang, not a standard Japanese word.
Anyway, this term is a slang that probably originated from the notorious internet BBS 2ch, and is used offensively to look down on people who are left behind from the internet trend. It is not an appreciated word.
It may be comparable to another slang from 2ch:
By the way, the character
Chiebukuro says that 情弱乙（じょうじゃくおつ）is short for 情報弱者.
What is a 情報弱者?
Chiebukuro has you covered again; it refers to a person on the wrong side of the digital divide, someone whose access to the internet is severely limited or nonexistent. It can also refer to someone who is out of touch with current events, or as an insult to someone who has asked a question they should know the answer to, or without doing basic research--like we might say in English, "What, you don't have access to Google or something?"