Yup, it's a trend. You're noticing right.
It's a phenomenon noticed by graphics card specific sites moreso than by others, because of the fanboy-ism that tends to be more prevalent.
Usually, it comes in three waves. Before the official announcement, there's generally a small contingency that joins and tries to conjecture what's going on. That group is usually a mix of both supporters and detractors, but they tend to be the more professional or reserved ones.
The second wave that comes along is the die-hard supporters. They create an account here, intent to post about everything and carry the cross, then they post once or twice and never come back. That is, until the next product launch when they forget they had a screen name already...
The third wave follows the second wave very closely. It's usually the people from 'the other side", ready to tell everyone how flangey their technology is and insult, berate, and annoy themselves into being noticed for a while. Those that don't end up banned (or worse - gotta love irate vigilante non-staff members!) for going overboard actually do remember their logins and wait around for the next time.
It's unique and rather interesting. I love studying this stuff.
Some days you get the bear, some days the bear gets you.