People commenting at the same time, without realizing others are jumping on the person as well, do not make a dogpile. The requirement is to join in with an angry group to yell at an easy target, or to get popularity points for being seen to agree with the group. They see that everyone else is doing something, and they copy it.
The original commenter typically does not respond at all, because they are completely overwhelmed or scared off. Once a dogpile has been established, an apology from the original commenter is less likely to be effective.
A 10:00 AM: "That song is retarded."
B 10:01 AM: "Um, that's really offensive."
C 10:01 AM: "That's not an okay thing to say."
D 10:02 AM: "Fuck you."
E-Z over the next 12 hours: "FUCK YOU, ASSHOLE."
A: "Sorry, I didn't realize that word was offensive."
12 different people: "Stop trying to backtrack, you piece of shit!"
Or another example is, everyone attacking one person, even though they weren't present, simply because one person is angry at them.
If you have ever witnessed a litter of hungry puppies all go after a piece of kibble or a table scrap at the same time, you can appreciate the similarity. They collide and climb on top of each other after the piece of food.
Likely gained popularity a word used for when, on a football field, a player is tackled by multiple players. A lot of high school football teams are named (insert name of school here) Bulldogs.
Also known as a pileup or a crush (the person on the bottom of the pile feels crushed under the weight of the others)
Other definition: The name of search engine that gathers links from other search engines in its searches (in visual imagery, having all the other search engines jump on your inquiry)
Other definition: A group of dogs or puppies all sleeping in a group in one place with their heads, feet, and bodies under, over, and on top of each other
Other definition: a mound of dog feces
Related word: bum rush
"I was running down the field with the ball and tripped on my shoelace which had come undone. James jumped on me, then all the rest of them dog piled on top of me."
2. A less rambunctious occurance in which one unwilling participant is buried in hundreds of pounds of human flesh.
3. A shout which precipitates either 1. or 2.
2. DOGPILE! - A scream. The rest are laughing. -