I subscribe to a few RSS feeds which tell me about the new web applications/startups/services. I am surprised at the number of web applications/services being produced at a DAILY level. My feed has at least 50 new sites mentioned every day. It seems like everyone is working on some Twitter client, online project management system, how you track time, how you track something, some kind of mashup,.. etc.
Most of these services do not charge money. With so many similar web apps, I don't understand how these services make money, how they attract people, how regular users find them or how regular users decide what to use. I am thinking people are overwhelmed at what's available.
If these services depend on online advertising, I think they will be spread thin. Because there are too many competitors and the fact that many users expect online services to be free. Unless you are offering a unique truly useful competitive service, I don't believe you can make enough money from advertising to pay for everything and have extra left over. Your site has to generate enough traffic to attract good advertisers. The other option is the Fremium model. Offer a free service and premium for pay service. I am seeing too many services which are absolutely free. I am guessing these are hobby projects. (I think I'll stop now as this is turning to be rant!)