Yes. But one should remember that some services that are popular today started with a very small user base. Programming languages have to start from one user (starting from zero is orders of magnitude harder - if you are not the first regular user, your project will most likely fail).

One way to achieve that is to have a "killer feature" or maybe a unique combination of existing features. For instance, a subject related to browsers is discoverability and search. If you are going to compete with the WWW without funding or support from companies/institutions, there's little hope that someone will provide a search engine. This means that users will have to pay for that service with their time (that's how Wikipedia emerged). One could think, for instance, about a content tagging system that users could share, to solve this problem.