Why does Google show different position of a website according to countries? For Example in uk there is site www . example. com show on first page by google but in us it's position, it shown on 2nd page...... What's the reason behind that.
They probably have different indexed page corpus for each country their server is located in. Ranking algorithms are skewed locally in favor of local results appearing first I think, but then why have 'search pages from the web an search pages from country radio button at the top'?
because Google delivered result ip specific(from which ip you entered query like us ip or uk ip), if your site having material or services that might be interested to uk audience then it will rank in first page although your site is located in usa. and some other factors also working for difference of rankings in countries i.e. search query & quality links of that particular region towards your website. lets say if you want to gain top rankings in uk then build niche links from uk local directories and search engines.
Probably Google have near 100 data centers over all the world, Its depends, from which data centers(Huge Server) the result page have return. So the positions will be vary from country to country...
Its utterly depends on google data centers. Google has huge num. of data centers world wide. According to the data processing of data centers some regional sites got good positions on google.
It could be due to your geo location preference set in Google webmaster tools, might be you have setup UK as your geo location. Also, backlinks are also a vital point while getting ranked over search results, you might have some good number of uk originated links that give your rankings a boost in UK search results.
The positioning of the website must be due to the location of your server, that is, the geo-location of your IP address.
This is a good point i forgot to mention, even Google itself says that geo location of your server also plays a crucial role in search engine rankings. You can also check this video for further help http://www.youtube.com/watch?v=hXt23AXlJJU
Google tried to bring you with results that are not only relevant to your search query within that particular territory but also to deliver your with the fast response. It locates a no. of servers and based on your preferences results are brought to you. The different between the different location is due to the relevance of content for that particular geo location (proximity).