single word requests - What do you call a Q&A user who posts a question but never checks back?

I have searched for a term that describes users who post questions and then disappear without trace. These users will post and write their questions in a great flurry, sometimes ignoring the basic rules of punctuation and capitalization, they will also plead for assistance, and conclude their posts with a thnx. And yet when regular users respond and politely ask for further information these newcomers will remain mute. Answers will be posted but receive no confirmation from the OP (original poster) that their problem has been solved. Only when a day has passed by, do users realize that these newcomers have effectively gone. Disappeared. Vanished. Sparito.

I am not talking about lurkers, users who sit on the sidelines and observe, reading content but never interacting or contributing. Apparently, lurkers are said to make up 99% of all Internet users.

In Internet culture, the 1% rule is a rule of thumb pertaining to participation in an internet community, stating that only 1% of the users of a website actively create new content, while the other 99% of the participants only lurk. [...]
The terms lurk and lurking, in reference to online activity, are used to refer to online observation without engaging others in the community, and were first used by veteran print journalist, P Tomi Austin, circa 1990, when her presence was noticed by other users in chat rooms, who queried her reasons for not engaging in chat. There were repeated inquiries about her identity and her refusal to engage in chat.

^{Wikipedia: 1% rule (Internet culture)}

No, I am referring to users who do make a contribution, who have taken the plunge, and seem to want to engage but then never come back (unless they have multiple accounts, which seems very unlikely to me.)

I have come to call them Hit & Run users; because they remind me of the expression hitman, they shoot a question and then run away. But is there an established expression, word or phrase used in social media? I have honestly searched but Internet slang dictionaries are no good unless you already know the term you're looking for!

Answer

This kind of user is called an ask-and-run.

It is even mentioned on Meta Stack Overflow: Dealing with “ask-and-run” questioners

---

Bonus: If we follow the same pattern, we can also come up with a specific term ask-and-idle for users who post a question but stay idle (but don't disappear/leave) without accepting an answer, commenting, replying to people, etc.

---

There is also the term Hit-and-run posting (thus hit-and-run poster) but it is a more general term and it is usually used for a one-off forum posting posted by a hit-and-run poster that ignites discussion. The motive of a hit-and-run posting is usually flamebaiting (posting a provocative or offensive message).

Hit-and-run posting refers to a tactic where a poster at an Internet forum enters, makes a post, only to disappear immediately after. The term comes from the hit-and-run crime on auto vehicles, in which the driver hits another car or person causing an accident and runs away. It is also known as making a "drive-by" posting, a play on the phrase drive-by shooting. The post often consists of a lengthy text making lots of claims that can be, but are not always, on topic.

http://en.wikipedia.org/wiki/Hit-and-run_posting