I'm not stupid. I think most people online are not stupid. But there always seem to be people who think they can assume a fake identity for whatever reason and have people believe them. What could the reasons be to become someone else online, to fabricate a backstory and try and roleplay your way through internet communities? Even though I think that people do have the freedom and right to be who they want to be online, I am going to explore the limits of this kind of deception a bit.

Five reminded me that in China people have to register using their real names and choose an avatar of the gender they are. The reason for this is simple: they want to be able to find people who speak out against the government easily and quickly.
In the west, broadly speaking, we are told to do quite the opposite: leave as little personal information around online as possible. You never know who might find it. Personally I find that very important for young impressionable kids to know, because it is very tempting to trust everyone you meet online, and who is half-decent to you. But that doesnt mean I would advice to blatantly lie about your personal circumstances.

In fact, I have found that even if I don't know many personal details, I at least know the people I talk to online. Even if I never met them in real life. There is a level of honesty that goes beyond knowing how many siblings you have or where you go to school. The few times I encounter someone fabricating an online persona, and trying to impress me with lies, I just have to laugh.
In the end I think it is harder to keep up a pretense life online than just not sharing some personal information. I also think that that kind of lying can and will only backfire. The trust and goodwill that you build up with people you only know online is easily destroyed if lies are found out. Much better to just trust that being who you are, is more than enough to have fun online and make friends.