Read Thread: Board archives?
I couldn't get into older post on a local board until I searched all the boards by keywords...then I could see really really old post from all the boards, but I'm not sure if that's how its supposed to work.
I'm not actually sure which page you're referring to, but I suspect you're looking at a list of "recent" messages rather than "all" messages. It's an important distinction! =)
When you're reading a board, though, if you click the "First" button, it takes you to the first message of the board.
If you want to poke around messages older than a year but not necessarily the very first messages on a board, however, I'd recommend the search boards option. You can specify the year you'd like to search from 2004 to the present. (Message boards began in 2004.) You could explore specific themes across all years as well.
It's also possible to look at the AQ Stats page which shows how many messages were posted each month since the feature was introduced. If you click on one of the months, it'll take you to the messages starting from that month.