... and look a look at how it's grown, especially in the past couple of years. I think it's safe to say the site income has grown exponentially in the past couple of years along with the influx of new users, and the increased popularity of bitcoin in general.
Lol, where are you getting this? Because every metric suggests otherwise, as in down ~50% over the past 2 years.
The site has grown a
lot in the past couple of years, there are a lot more users and a lot more site activity as well. Same with bitcoin in general, there are a lot more people interested in it than a couple years ago.
So I think it's safe to assume that if you're planning on advertising on Bitcointalk, it'll cost quite a bit more than it did a couple of years ago due to how much more traffic the site gets, since your ad would be getting many more impressions.