As your fortress progresses, some dwarves could keep records of their days on stone tablets, vellum, or paper. Or maybe you could even craft leather-bound books for your dwarves.
When your fortress is destroyed, and you return as an adventurer, you should be able to find and read these journals if you are a dwarf. If you are a human or elf, they should be incomprehensible, since they are written in dwarven.
Sample journal:
Granite 4, 1056
"I flirted with Inod Skullscratcher today. He is so dreamy! We have so much in common! We both love tentacle demons, onyx, and chain mail! I want to live with Inod forever."
Onyx 12, 1057
"Inod Skullscratcher and I had our first child today. We named her Aksi, "The Terrible Red Pains of Birthing".
Dolomite 1, 1058
"Aksi was killed by a crocodile today. Her body is just beginning to decompose. She deserves a proper burial!"
Dolomite 25, 1058
"I'm tired of living. Today, I am going to kill myself. I will close my eyes and dive into the chasm. Goodbye, world."
More ideas: the broker could keep a record of every transaction you ever made, when you made it, and who you made it with. The bookkeeper might keep an annual record of stocks. The diplomat could record the relationship between other political entities and your fortress. Etc, etc, etc.
[ October 26, 2006: Message edited by: grendel ]