That's because Twitter just began rolling out a new search infrastructure that will allow anyone to search every tweet ever published publicly. That might not seem like a terribly profound deal, given that this information was technically out in the open already.
But as anyone who has ever searched for an old tweet knows very well, "out in the open" is a relative term. A tweet from 2006 may technically be accessible, but it's buried under eight years of digital sediment - thousands, maybe tens of thousands, of later tweets, each appearing reverse-chronologically, fossilising the oldest tweets further, linking none of them to search results.
In fact, you can think of Twitter's incomplete index as a corollary to the whole right-to-be-forgotten debate: In both cases, the material in question is still online - but since it's not tied to a search index, it may as well not exist.
Twitter is rolling the index out by degrees: While the underlying infrastructure went live on Tuesday, a post on the platform's official blog says they'll continue tweaking how search results are displayed and rolling out "new product experiences," whatever that means.
In either case, you have a little time to ponder the ancient tweets you'd most like to uncover. Or to clean up your own digital footprint! You decide.