This is something which really irks me too.
Especially when the post has been answered then someone else says the exact same thing but they are the one who gets the "credit" for giving the answer - helloooo I said that two days ago LOL.
I know exactly what you mean..this happened to me a couple of weeks ago...sometimes you feel completely invisible..but i just think WHATEVER!!:lol:
As to skim reading 4 pages, TBH I would actually assume that after 4 pages of information, there was probably nothing else of import that I could add - on this occasion I would probably skim read the names of the posters rather than the thread before even thinking about rereading and then posting LOL.
Also as well as reading posts, use the search facility as there is so much great information here.