I'm relatively new compared to others...
There might be more people now with so many kids out there with smart phones thinking this is another social chat site. Many of the more mature and intelligent members who cared about using this place as it was intended have left, some sadly passed away and some just decided it was not a place to bother with. There are few good users that have been here for years but there are more of them that are not shining examples of quality or a good representation of what the site was intended to be.
No, I would say at least 2/3rds of the originals have left. Its still busy around here but not crazy busy like before. Now many questions become orphaned or maybe 3 or so answers, with at least 2 non answers vs about 10 answers with about 7 decent ones in the old days.
yes; the format was changed from the green version to the current blue, and that caused some defections. then there was the recent Great Glich Storm; in nov 2015 yahoo brass said they were "disinvesting" in Ya; this summer Verizon bought Yahoo's internet biz, sale will prob be finalized in 1st quarter '17, so yahoo's prob continuing w/ its disinvestment in Ya, and that means more deterioration
There were more users in the past. Most left due to the purple format, the glitches and the thrill wore off.
Total user numbers are about the same, but since twitter and all the other chat sites came along, active users are down.
More trolls now, less good answerers now.
more and more normal too.