Upload & Sell: On
Yeah, it doesn't keep track of which posts you have read or not. You can keep track of which pages of a multi-page thread you've read tho. By clicking the number of the page your browser will remember that you clicked that link and render it a different color. Make sure you have your browser set to keep history long enough for that to be useful tho. I set mine to 1 year.
But to me this is an issue of brain power and reading speed. Get some books on memory building maybe and take a free on-line course on how to skim a document. Those ARE skills and there are skill-levels to it so that's not a put-down or condescension.