Yes if u have a good idea on how to develop it. For 365salary.com, you can develop it this way. Have ppl from all around the world coming to your website and poll "which country they are from, what's their job, and what's their annual salary". If you get huge enough of data, then you can summarise them and then job seekers can goto your website to get an estimate of average salaries for different industries in different countries. You can then earn advertising revenue from Websites or companies offering job placement or matching services.
Maybe others can put a value to this kind of developed website?