Oversharing has become de rigueur for parents. Posting sonogram pictures on Facebook has replaced the snail-mail baby announcement; the annual family letter is now a stream of daily updates on the trials of parenting and the triumphs of our offspring. One person’s electronic scrapbook, however, is another’s narcissism.

Enter Blair Koenig, the woman behind STFU, Parents, a blog that collects and publishes the most egregious of the parental overshares and sanctimony on public social media sites. Koenig is a 30-year-old childless Brooklynite who until recently ran the site anonymously. She has revealed her identity, as this April, her book based on the blog site is due out.

In the site’s 31 / 2-year existence, Koenig said she has learned that there are a few common errors parents make online. Below, are a few of her favorite parental share fails:

* When a Facebook friend posted that she was “possibly having the best week ever :)”

A parent friend wrote back: “Just wait til your lil first child is born ;-) Out of the world feeling for a first time mom.”

* Another poster wrote that she had just passed her dissertation defense. “I’m [a] Doctor!” she celebrated. Several friends responded with cheers, including one parent who added: “Yippee. How exciting. Now you need the title ‘mommy.’ Sorry, I just know what an amazing mom you’ll be.”

*Another parent announced her daughter’s entry into “womanhood” on Facebook:

“OMGoodness. My daughter has ‘officially’ begun puberty!” She is only 10 years old. ...”

* And, last but not least, there was the photo of a bright red smoothie with a caption, “Mommy’s first placenta shake. It tastes like heaven. I put lots of pineapple, orange, and mango sorbet. Yummm ...”

Janice D’Arcy is a Washington Post staff writer. To comment, visit washingtonpost.com/magazine or send e-mail to wpmagazine@washpost.com.