I seem to recall there was no such place as AIBU when I first joined, people just used to write it in their thread title. Although I might be remembering wrongly.
At any rate, I don't recall the in depth analysis and pulling apart of posters that goes on now, from when I first joined. But I suspect that was more because I used to hang out in the baby threads.... then I went on a long break from about 2005-2010.
In the 4 years since I started posting again I don't think it has changed much.