>Almost every website is unprofitable in itself, and only exist to serve as a person's or company's marketing interface. Websites ARE the ads, because that's their point. The web is a giant marketing device to sell stuff, like your resume or your local plumber or your open-source software project.

This works fine for a business that sells direct on the internet, or a company that advertises themselves there (like my BigCo that has a website so people can learn about it, find people to contact, etc.), etc. It doesn't work so well for a company whose product is intangible, most notably news companies. How is NY Times going to stay in business if they don't make a profit on their website? In this age, people don't really want dead-tree newspapers any more. Also, sites that don't really have a product can't survive by selling stuff. Reddit, HN, etc. are good examples here; how is HN making enough money to operate itself? Basically, it isn't, it's run through goodwill by a VC company (though it might also be a form of advertising in and of itself). Smaller, more specialized discussion forum sites are also like this, probably to a greater extent: unless they're being financed by some sponsor (which is then likely going to advertise on it directly), they need a way to pay for themselves, and that usually means ads.