Does SEO on a website work on a country basis or does it work globally?

Javaid Anwar: Does SEO on a website work on a country basis or does it work globally?
Just something i want to try and clear up and wonder if anyone can help with this.
Does SEO operate on a single market basis, i.e. a UK site will only SEO well for the UK market, or does it capture many markets simultaneously.
If it is the case that SEO works primarily on a single market basis, what is the best approach to make it, ‘multi-market’?
Finally does anyone know how it determined that a site is a UK site or US site?

Answers and Views:

Answer by Dotcom
seo brings our website ranking in search engines, so search engines are not for certain country or certain regions its global to access anyone we have to bring our website on the top 10 through the related keyword search on doing seo.

Answer by Emmick
Where a site is hosted will have an effect on SEO, a UK hosted website of equal SEO value will rank higher than a US hosted site of equal value in the UK! and vice versa