I was born in 1984, and I feel incredibly lucky that I grew up at the tail end of BBS's and the start of the dialup era. Things were changing blindingly fast, but it was still small/niche enough that you still had a strong sense of community, hackers dominated, not companies, and we all had this feeling like we could do anything.
Even the broadband era was great, too. For me, it was the mid-2000s when everything really starting going off the rails (Facebook + iPhone, mostly).
Being born in 1981, the mid-2000s feel very weird to me too -- partly being in grad school in that time (and so somewhat isolated from the broader world) and yeah the rise of cell phones.
Born in 1988. Things were cool until around 2007, at that point everything great about the internet rapidly started dying off, though at first it seemed kind of exciting that it finally seemed to be getting global recognition, it was really the beginning of the end.
I was just a kid for most of the 2000s, but I was a user of the internet since way earlier than I should probably have been. Around that time is when I remember it kinda declining too, the forums that I frequented started getting closed down and my classmates uploaded photos with me in them to this newfangled "Facebook" thing, which horrified my "never say your real name on the internet" sensibilities.