Many people that email me about development are looking for ideas about what type of names to develop and how to monetize them. One easy way to come up with ideas, or see what has worked for others is to check marketplaces. The biggest website marketplace today is Flippa, with thousands of sites listed, but there are other sites and brokers selling websites without the junk. Many of the smaller marketplaces feature larger, higher priced sites and often provide more information in the forms or powerpoints or webinars which can provide further insight into their business models.
I have looked at previous sales and active listing with bids to see what other successful webmasters are doing. While you should not copy a site exactly, you can use their ideas and strategies on your own sites.
I’ve spent a few hours each week looking at Flippas top sales, and have noticed that a few of the top selling sites each week have been shipping or dropshipping physical products. Other top sellers have sold digital products like eBooks, plugins, or even phone applications. Content sites sell well, but to hit the big numbers there needs to be something more besides just adsense. Affiliate sites also have sold well; ones selling higher end items tend to do better from what I have seen.
After looking all all of this data I made a list of the industries and keywords and now watch for expired domains that contain them. If you already have domains, search related keywords on the marketplaces and see what comes up and investigate what they are doing to monetize the sites.
Take a look at Flippa, Latonas, BuySellWebsites,WebsiteBrokers and other similar sites to generate some ideas and see what is working for other developers. Do not be afraid to ask sellers questions, even after the sale. I have had many help me out by providing more information.
Another thing to think about is that many of the websites that do sell for large amounts on Flippa often have horrible domain name, so the new owner might be interested in your domain name in the same category. If not, you own the better domain so it might be worth developing and seeing if you can follow a similar model.