There is no restriction my friend. I received 90 percent of my traffic from Google. I prefer organic traffic compare to other traffic sources.
No, I do the work myself. It's not difficult. Just keep writing good content, research good keywords relevant to your content, and get links.
Ok now I know why.. you website is since April, 2004 and it's your specialty .. that's what is making content vcery unique and attractive .. congratulation
Yeah there is no certain limit mention! i usually get 30k monthly for one of my site! it depends upto your working strategy and link building
yes sometimes i do get a that much visitors and sometimes i get a little less than that, its not consistant but yes i do get it on quite a regular basis.
there is no limitation on this. one website i am working with received 3000 visitors from google a day.
I have never seen any evidence there is any sort of limit. The best I have done is about 200,000 visits from Google to a single page in a single day.