After reading a few of these ideas now, I see that many people want to rely on advertising for their projects. However, I believe this to be a big mistake. No one likes seeing ads all over websites and the fact is, ads are much less profitable than that used to be.

While your idea is interesting, I think you need to come up with a better way to actually make a profit from it than relying on advertising.

While I think you do have to be careful on relying solely on advertising I think sites like Digg have shown that advertising can be a model worth using if you are able to create a space that is addictively interesting.

Add a little seasoning:
Allow users to subscribe to multiple cities via RSS so that they are more likely to visit the site later. A "local sales" section would allow users to list local deals they found in the city so that other users can become aware. This may be of great value to travelers who are not familiar with the city. (A different kind of "news".) Basically you can combine the power of news journalists, with the power of online comments, with the power of local area sales.

I think localization has a lot of potential.

Techguy I agree about advertising as a model. And Maurreen the localization is key you are right. Look at google they are majorly working on this right now down to the with some of there side projects. this just says it is important.
I think that this would be extremely successful as long as ALL places were covered.