Barberry,
You're right about the internet and other public information drawing more hunters to certain areas. And you're also correct that this will impact grouse populations in a specific area, such as one specific clearcut or all the good spots along one forest road.
However, I'd suggest that the much bigger issue at play in this discussion is the maturing habitat on the ANF. If you're from the area, I don't have to waste typing time explaining all the reasons that keep the USFS from cutting trees, but the bottom line is that fewer logging projects take place on the Forest each year, encompassing ever-smaller plots, and so less grouse habitat comes into being.
You're exactly right about the '90s being a good time to hunt grouse up there. Setting aside the impact of normal population cycles, that period came about 10-15 years after the most recent peak logging activities on the ANF, the late '70s and early '80s. Since then the USFS has been so mired in lawsuits and related hassles from groups like the Sierra Club that they can't hardly get a tree cut.
It's an unfortunate case of emotion trumping science (stop me if you've heard that one before). Sadly, though, it's the wildlife - and by extension, us - who pay the price.
Of course, the birds pay with their lives so that cost is a lot more dear.