Have a look at
http://www.ferret()com.au
&
http://www.hotfrog()com.au
(replace the brackets with dots, i don't want them to find this forum)
These guys are the directories you are talking about, but within Australian only.
for hotfrog, I am not 100% sure how much they charge
but for Ferret()com.au, they add companies in their field (manufacturing industry) for free. Then 1 month later, they call them up personally, and ask them to "upgrade" for a relatively resonable price paid yearly.
The upgrade consists of not that many things, but companies usually wants to do it, just to "out do" their competition. Then BANG, there you go, you get income like that,
So having a database of like 10,000 companies, 10% (worse case) of them willing to pay you say a little under 1k/year, for the minimum upgrade, thats 1000 x 1000 which is 1,000,000 a year.
Now, WHY would they want to advertise with you? Well because you HAVE THE TRAFFIC, that is the key point. Now HOW do you get the traffic? Well, you tell the 10,000 companies that if they make press releases about their product lines they will get more traffic. Hence you have "relevant" content for your website. Ofcourse combining other
SEO techniques which you will need to figure out yourself, you will eventually become number one when it comes to searching for the specific keywords which relates to your website.
for example, look for "fork lift hire" on google, and ferret()com.au will come first, why? well click on the link, you will see that its a "press release". This is Relevant content, and "rich" content, which google loves.
Ok, now that being said, how else can you make money? well simple, sell advertising space on your website, island ads within press release (also, if the company who wrote that press release pays more, they will be able to remove that island ad). Banner ads, newsletters etc etc, your database is worth $$$$, and the traffic you generate will get you even more money.
SO YEH, thats just some experience I wanted to share, take it or leave it.
Cheers