You could quote the page, with a simple statement like "marking my spot". Otherwise, I have no idea how to do that. Perhaps keep a post it note next to your screen and write the # of the last post you read?X's 3!
I have a silly question that is probably staring me right in the face. I've been reading from the first post, but can't get through it all at once, there's a lot that has been going on with this sweet lady, anyway, is there any way I can just post the page I was on instead of clicking through until I hit the page? Make sense?