I put aside a low-tech time capsule at the turn of the Millennium (on the pedantic date, not the usual one, of course.) It includes a lengthy comment by my mother, who had died just a little before, photographs, foreign money, I forget most of the rest. I did write a long letter - big surprise there. I imagined what it would be like to read a letter from one of my ancestors 100 years ago, and wrote accordingly. I still remember bits of it, but I intentionally didn't keep a copy.
What impresses me at present is how much of what I remember is already dated. Seven years out, and already I can detect a faint ridiculousness about some aspects. I wanted descendants to know something of what sort of family they came from - how we thought, why we did what we did, including what trends I could see from my own forebears through me. I thought it might be a comfort to a great-great granddaughter to see qualities in herself that came as a sort of legacy.
At least two of my genealogical lines are notable for people with great memories, large vocabularies, and out-of-the-box thinking. The sort of intelligence one finds measured by standardized tests is also prominent. I thought that might be a source of pride for a descendant, and now that I look at it, I was quite prideful about my relatives and myself on that score. It never became a completed thought, but something like "Your great-great grandparents were very clever people who knew all sorts of things" was not far from my mind.
What we now call intelligence may be a mere curiosity of ability 93 years from now. We think of memory, vocabulary, and general knowledge as skills exemplifying Smart in our era. But with search engines already making me obsolete, and the likelihood of being our rapidly becoming able to purchase intelligence as a brain augmenter like software, or as a gene we can have installed in our children, what descendant would care if we were intelligent - even if we were among the most intelligent? So what? It might be no more of an honor than we would regard an ancestor of our own who had memorized whole plays of Shakespeare, or had beautiful penmanship, or estimated distances well. Mere curiosities.
What qualities might be thought to last, then? Exceptional abilities in design, perhaps, or of art, though I can imagine even these being superseded by technology.
We might hope that character will endure. Kindness, generosity, and self-sacrifice might still be valued.