whats the link between unique visitors and estmated revenue?

Similar questions have come up a number of times. Here's the formula:

* Your site map - how many pages on your site.
* How many ad units on each page and what type (300x250, 160x600...)
* How many visitors and average page views they'll generate. (This includes how you'll drive that traffic to the site.)
* How many page views do you estimate for each of the pages.
* Total ad impressions then that generates for each size ad.
* Going CPM rates for each size ad in your industry. If this is Google AdSense then plug in estimated CPM from that.
* Do the math and you'll come out with a number. And do a "best case", "worst case", "expected case" scenario.
* Note that other variables will affect these rates. They include whether an ad is above the fold or not, context of the pages, etc. But this will give you a ballpark for business plan.

Best of luck,

Your assumptions are correct, it depends.

Also, you mentioned the following:

"as I need to put together some financial figures for a new startup"

Just don't, don't try to find a good answer about this because there is none, at least not for a site that it isn't generating millions of visitors per month. I am one of the "crazy" souls that believe financial figures based on website visitors are just useless guesses, they don't add any value and any respectable investor will tell you that - IMO.

I will look at other areas of your business that have the potential to generate the financial figures you need for your startup, how are you going to be generating revenue, will you have a subscription based service, are you selling something in your site, etc...

I hope this helps, not too many people will agree with me, the above is just my opinion.

Good luck!

Ricardo.