When you give an answer to a problem and get no aknowledgement back ,that the problem is solved or otherwise. I know they are in the minority but if they let us know if our soluton has worked we can use this information for future reference to advise others correctly. Also i find it slightly ignorant,but perhaps its just me.
Cant work out how they forget,they only need to check their postings from time to time. Seems to me they get their answer and never return or they do return,check their postings and cant be bothered to reply.