I found myself in a weird position. I gave a dedicated server with 24 ips where I host some of my domains. Well, I have a site which is in top 10 for a popular search term on any google tld (.com, .de, .it, .ca and so on) and for any ip location. Which means I get traffic from all around the world. The site is in English and has only backlinks from English sites. Now, if I search the same term with google.xx (where xx is my country) and select the option "Search pages from .xx" I see my site at #1. I also have to say the site niche (soccer) is very popular in the .xx tld zone. Still, there are no links from any .xx domain to my domain. Furthermore, there are no links from any of my domains (which can be associated to the .xx tld) to this site. Basicly, there is no link that can prove this association. In conclusion, Google is right: the site belongs to an .xx webmaster (thats me) but the audience is worldwide (there are only 1% visitors from .xx) I have now two options: 1. Google is stealing data through the google toolbar. Plain and simple. I uninstalled it anyway but maybe there are leftovers in the computer. 2. Google is making some ip associations between my other domains and this one since I am on my own server (I am not sharing the ips with other sites). What do you think? It is very annoying to build english traffic starting with this handicap.
What about domains registration? Are the all your domains registered for the same person? Google takes this information too.
Check your whois information. I know for sure that Google takes into account this information. Using it Google associates all of your domains.
Firstly if you knew how they did it then surely you would manipulate it which is not right in the first place. Secondly, Google doesn't need the toolbar info as there are 99% other people who use it and don't even have a site. Thirdly, sharing different ips doesnt matter if all your nameservers are the same. Come on who are you trying to play in the first place? Take my advice and build a site for the traffic you want, forget tlds and forget search engines and forget other factors, build a good solid quality site and you will never ever complain after a few months or less. Just being honest and giving you a good advice, if I was harsh then do excuse me as I didn't mean to be. Best of luck.
Ok, I have other examples that can prove Google does more than this. I have protected domains who show up in other searches only for my .xx tld even though they are written "good english" (not like mine) and have no links! I guess Google uses more than this whois check. But if I put a whois guard now on my domain it will be useless since the association is already made? And this is in general not normal and not fairplay. I know such associations will hurt your general listing (on google.com)
Much appreciated On this soccer site I have content and people come daily. It is good content, I have no worries for this one. However, there are sites which rely only on SE traffic and who can make a fortune. For example, selling pills over the internet is done 99% with fresh SE traffic. I am worried, since Google is that smart, that I already have a starting handicap since I am suddenly associated with other tongue/language/geolocation (in Europe, of course). But it is not US/Canada/English which is my main target even though I write for them, not for me So, you see, the problem is not as simple as it seems.
I know brother.. But whatever your end target is, you cant forget what Google appreciates the most in long term.. quality! See if you are building a site for pills.. and all that lol.. then firstly you should target what you are writing for. Google doesn't mind it as long as you can be unique and people links to you. However, if you go targeting other locations slowly enough while publishing articles focused to another location and the new one.. it is quite logical to think that you are expanding and anyone will reward you including Google. Just my opinion
In webmaster tools you can specify a specific geographical target user location for your sites, this may help targetting visitors from the UK!