cellphones.com is a very unusual example and used as the classic example to justify investing in domains.
Just about no other domain - at least none that I know of - gets that sort of revenue from parking - and if it did it would be a prime case for proper development.
Typically on a usual domain you will not even cover reg fee. A fairly good keyword may get $2 or $5 per month, and a good one $500 or $1000.
There are several on this board who do better than that by carefully researching estimated type-ins before buying the domain but they are much better at it than the rest of us and deserve their reward.
I very much doubt you will get a previously unregged domain that will get $500 per month let alone per day - and if you do - well done!
Some of the good names dropping will get more than that.
Money is made by you directing your domain name to a name parking company that then puts a whole load of highly targeted advertising on that page, that they will have got from google or overture or whomever.
The person who has typed in the domain e.g. cleaningfluidforsoiledtrouserknees.co.uk is probably expecting to find companies who specialise in that search term.
He may or may not find that company amongst the advertisers on the page, depending, amongst other things, on how well you have optimised the page to attract the right adverts.
If he does find an appropriate advert he will click on it and go to that site.
The company who advertised the product, meanwhile, managed to get their ad in the right place at the right time by, for example, subscribing to google adwords and setting up a campaign and ad group focusing on that product.
They will then have set the distribution settings for that advert to 'content' which would allow google to distribute it to any specified site that google has an adfeed in place for.
The advertiser can choose right down to the specific url where they would like their ad to show up.
They then have to choose how much to pay in order to send their ad up the rankings.
The click through onto that ad to the advertiser costs the advertiser whatever fee he bid through google. (actually just 1p more than the bid lower that his as google has this automated)
Google extracts that fee from the advertisers account and gives a proportion of it (perhaps 65%) to the parking company. The parking company is informed by google of the click through and accepts it as a valid one and not a click fraud one and pays the parking company that money (monthly probably).
The parking company then pays the domain holder (you) a proportion - (perhaps 30 - 50%) of the revenue they got from that click-through at the end of the month.
You get that paid to you by cheque, paypal, bank transfer or whatever.
If you can get more than approx $0.60 per month equating to approx $7.20 per annum and you are paying say $6.90 reg fee every year then you have a profitable domain.
However, if you get less than that it can still be profitable to hold as when domain portfolios are valued, the ones I have seen do not tend to deduct reg fees from the revenue figure, and they then sell the portfolio on anything from 2 to 8 (or whatever) years revenue prediction.
It is of course up to the buyer to determine whether they think that is value or not.
Many domains are better to develop than to hold as they sound nice but do not get type-ins, and it is more likely that you get one of these.
Sorry for the long post but I have answered this question on more than one occasion so I thought a full written explanation was justified.
Good luck!
-aqls-
