Oh, the @ of it all! D it!

Rep. Anthony Weiner’s troubles — sending pictures of his junk to the public Twitter feed, lying about it, and then admitting it while refusing to quit his day job — were caused by the mistake nearly every Twitter user makes at lease once, the Huffington Post reports.

In Twitter world, people can use special software that’s been developed for power users. Or they can use the company’s Web site. Or they can use the old school approach, which is to tweet via text messaging from a phone. And to do that, you have to include the correct codes.

A tweet meant to draw my attention and mention me, for example, would start “@roybragg,” followed by the message. Everyone can see that message, and I would get special notification that I’m mentioned in it.

But a private message — say, pictures of your junk, intended for a woman you are e-stalking — would start with a “D,” indicating it’s a direct message. If you were sending me pictures of your junk — and I cannot emphasize this strongly enough: DON’T — you would text “D roybragg Check out my junk!” and include said junk picture.

Forget the D and you end up with something akin to Weinergate.

Twitter misfires happen all of the time. A fellow journalist at another paper did it once, intending to message me with some chisme about her workplace. Instead, it went everywhere. Thankfully, it was devoid of salacious detail and she deleted it quickly. Last week, I did the same thing to her. Not to belabor a point, but there was no junk involved in our exchanges.

But that’s what Weiner did, according to the transcript of his press conference.

Remember: If you tweet, know your Ds from you @s. And be careful with your naughty junk pictures.