1. I think most city names will be taken. For those that are not local government agencies may end up being able to grab them from you if they decide to use them (depending on local laws and the registrar used). You will need to be a bit more imaginative in naming.

2. I don't think there is much to worry about with search engines as long as your site is well structured. With such a general site you need to encourage deep links to improve indexing at topic level.

3. Before spending too much time on this think about your target audience and what sites of this nature exist already. A search on London for example will swamp you with a host of directories and review sites covering various topics from pubs to folk music. You will need to be very tightly focussed to get anywhere in the listings for major cities. A more generalist approach may work for smaller towns or non-tourist regions.

In my opinion it is best to go with one mega-site that lists all cities together. www.example.com/CityName looks very nice in my opinion. And you can always create redirects that will take users from CityName.example.com to www.example.com/CityName if you receive type-in traffic.

One big mega-site is useful because it is easier to manage it later and interlinking the cities does not look spammy.

You don't think someone thought to register cityname.com before you?

Assuming you can get the domains you want, I don't think it really matters what style you use.

[edited by: phranque at 9:54 pm (utc) on Jun 18, 2010]
[edit reason] exemplified "cityname" [/edit]

you might be better off using a country specific ending like .co.uk, because it might help you rank a little bit better in google.co.uk.

I have a similar question -- though not related to geography.

I'm opening a new section of an existing web site. Which is the better way to have the URL?

http://section.example.com
or
http://www.example.com/section

In my opinion, the first one is better because it is easier and shorter to type. But then, few people will reach that section of the web site by typing.

Another person in my office likes method 2, but can't say why. It just looks better to her.

Whichever way I go, I'll 301 the alternate. But I'm wondering if there are other pitfalls I don't know about that would make one way better than the other.

I've looked at some big web sites, and the results are mixed, even on the same site.

For example,
www.example.com/store redirects to store.example.com
retail.example.com redirects to www.example.com/retail

Thoughts?

[edited by: phranque at 9:49 pm (utc) on Jun 18, 2010]
[edit reason] unlinked & exemplified domains [/edit]

I would start with a memorable short brand name to be your domain name.

Then you can have www.example.com/country/cityname/index.html

[edited by: phranque at 9:58 pm (utc) on Jun 18, 2010]
[edit reason] exemplified location [/edit]

I'd go with a brandable domain name and use city names in sub-domains, ie: cityname.example.com

Word of warning: Google will place maps and shops and local content above any of your content so at best you will be ranked near or below the fold where not as many people look. If other sites are already well ranked for that city name you won't rank on page one no matter what you do. Dot com geo domains can cost millions to buy and if it's not a popular city or a dot com you may get very little type in traffic.

Geo domains - they used to do extremely well but have been cannibalized by search engine content.

[edited by: phranque at 9:59 pm (utc) on Jun 18, 2010]
[edit reason] exemplified "cityname" [/edit]

I've looked at some big web sites, and the results are mixed, even on the same site.

For example,
www.example.com/store redirects to store.example.com
retail.example.com redirects to www.example.com/retail

Thoughts?

when "Example" is the "largest technology company in the world by market capitalization" they can do whatever they want and not worry too much about what is "right".