I have a site which is not specific for any country. However, I found it for two key terms of my site, it ranks no. 1 and no. 5 in Google.co.uk but it cannot be found in google.com even till the 100th position. Does anyone have such kind of experience to share?
In fact, it is also good for me to be rank good in Google.co.uk since the income of the site is mainly from adsense. I just wonder why this happened. And thanks, I don't really realize that I have to consider the TLD when I build links.
I have had similar things, look at where your site is hosted, also what links point to it and where they are from whether .com or .co.uk also where these sites are located. Building good results in the local searches requires links from those regions. If you want just google.com which I find these days is really USA market more than anything.
Google webmaster tools allows you to set a geographic region that you want to target, so you might want to define that.
May be your domain extension making google to target some geographical area. Check this for more information.
Google decides regional ranking of a website based on a few parameters, TLD and the physical location of the server on which the website is hosted. Also you can define the same using Google webmaster tool. Now since you are only concerned about traffic, it hardly matters for you but for some people this scenario can have serious repercussions. When everything fails then KML works.
What is your domain name? Without this information it would be impossible to give an opinion. It might be your extension, the location of your host, the location of the sites you are getting your links from etc.
I can't speak for others but I like to search only from google.com, so regional ranking does not hold much significance for me. However, I do get some traffic from regional google sites.