This is Your site and You can do whatever You want concerning this issue.
In general I think that ads by for example 'Google' would make quite complex restrictions on the site as the previous writer told. This site would not be 'free' after those ads, but the people putting there ads would like to have influence on the contents of the discussion. It might also mean that you would loose several of the contributors for this site.
The important issue is that you are now using so much of your time to run this site that probably must get some kind of income for running it. It is maybe worth of trying to find also other solutions how to run this site without money or making money to be able to run it.
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1)
One possibility is that you could maybe find volunteers to do the administration.
a)
Somebody in a rather similar position as you were with your business some three - four years ago, might be willing to do the administration free for some time, because she/he would get so much benefit by learning from the site that she/he would do the administration to increase her/his business by doing it.
b)
Somebody studying the renewable energy field at an educational institute might be willing to do the administration for the reason to learn this stuff.
c)
Somebody, a retired person maybe, might be willing to do the administration free, because of not in the need of more money and thinking that it is the best way to utilize her/his time.
d)
There could be a network of people, who would do the administration free together so that nobody would need to invest too much time in it.
e)
There are certainly more ideas within the people.
2)
There might be other ideas how to make money by running the site.
a)
If 'Classifieds' would be utilized effective ways that might create money. There are certainly quite many people reading this site and for that reason 'Classifieds' is a good place sell the stuff, many people would see the ad. You might put a fee for putting an ad on 'Classifieds'. 8% - 10% of the price of the goods would go to the site? 'Classifieds' could be changed into a commercial part of the site. People, who don't like business wouldn't need to read it.
b)
There are certainly other businesses besides Yours, which have learned a lot by this discussion.
Maybe some other people doing small business on the renewable energy field would come to help You with administration/money. Maybe people like 'WindstuffEd', 'Jerry', 'windcruiser'...
c)
Maybe You/we could work out cdroms using the information available here to be sold to make money to run the site. For many people it is worth of paying 20$ - 50$ to get the information home on a cd rather than paying for the bandwidth to search and download the information.
d)
other ideas?
- Hannu