Several things can go wrong, however especially if you have different portals for the same language countries, i.e. America, UK and Ireland.
You will want your UK site (mysite.com/uk/) to get Google’s sitelinks to UK pages. The international set up should aim to produce different site links for each of the countries as well as show different language/countries website versions for different country users.
International website objectives:
Encourage the relevant versions of the site are being shownSommerseo in all countries accordingly, for example, mysite.com/uk/ for the UK and /us/ for the US.
Encourage correct sitelinks being listed for each of the countries, see Apple.com/uk/ for an example.
Ensuring correct international indexing:
– Make sure that each country section of the site is clearly marked as such (country tags in HTML, clear text links, clear and obvious navigation, use local currency/date/measurement formats).
– Add a link tag to the header of the templates to tell Google the corresponding homepage for any given portal. For example, on the UK portal.
This should be placed in within the head area of the HTML page.
– If you have different physical addresses/phone numbers for each country, list them clearly in the relevant sections.
– Go to Google Webmaster Tools and verify each country’s subdirectory/portal as a site. Use the geo targeting option to set each subdirectory to the relevant country. See the next section for clear instructions.
– Create separate HTML and XML sitemaps for each country. Submit these XMLs.
– Get good quality incoming links from UK sites to the main UK pages, quality US links to the US pages, and so on.
Google Webmaster Tools for International sites