A person who issues a final, meaningless and annoying reply to a text thread between 2 or more people. A "dingle-texter" is the type that always has to have the last text in the thread, regardless of how mundane and redundant is it. This final text forces the "normal texter" to keep having to look at the thread without getting any real enlightenment out if its ending.
Normal Texter (NT): I am making cookies tomorrow. Would you like some?
Dingle-Texter (DT): That would be great. When will they be ready?
NT: About 1PM.
DT: Let me know when ready and I will pick them up.
NT: Will do.