re the TLD ( extensions ) aspect..
I search when using Google using Google.com, Google.uk, Google.fr and Google.de, and occasionally others..
IME how Google handles TLDs depends upon where one is and which Google.TLD one is using..
I have seen some .infos rank ( I have a handfull, hangovers from when they were free with a dotcom ) I have never seen a dotbiz ranking, and have never bought any..I have no intention of buying any of the myriad new TLDs "invented" by ICANN to swell their coffers ..I see .coms ranking far more than .nets ( I rarely see a dotnet ranking, again I have a handfull, had them for over a decade )..and see some .orgs ranking..( more so than .nets )..
I rarely see a .fr ranking outside of a search done on Google.fr, but on searches made in Google.fr, the .frs are about 50/50 with the dotcoms..similar situation with relation to the .de and other "national" TLDs if one searches from their national Google TLD..
But obviously if one is searching in French one is likely to get back more .fr domains with the .com ones..
Most French businesses ( myself included ) buy the dotcom and the dotfr..others I buy if the destination countries are close enough to ship goods economically to customers there..Where we have OEM manufacturing ( "overseas" ) done I also buy the "brand" name in the respective country's TLD..But, never seen any of my "overseas" TLDs show up higher than my dotcoms or dot frs etc for either the "brand" or the keywords, then again I tend to keep the overseas sites pretty bare..
The UK is an odd search market..I would expect a lot of .coms to show up in SERPs there, and , as I have said here in the past , I never gave the .co.uk TLD any "cred"..because anyone in the world could buy one, and make believe to "Brits" that they were a British business, so I only ever bought a few "defensive brand protection " ones..I also have a registered business in the UK, it uses the same "brand" so I bought the .UK..
IME Google SERPS in English ( wherever you are searching from , Google.com or Google.uk, ) are not like any other language version, for a start they are far more "competitive", It would appear from some comments here that a high percentage of U.S.A dot coms show up in searches made from the UK..But I do not hear of the U.S.A Google.com SERPs having a high percentage of United Kingdom .co.uk or .uk sites showing up in them..
French SERPs also have a large number of French language sites from Canada appearing , ( usually with .ca ) depending on the search query, whether one searches in Google.com or Google.fr..the "trigger" is the language..
I hardly ever see any non dot coms ( including .us or .in. or.co or .co.uk etc ) when searching Google.com in English..
What Google says..is not what I see, nor what I have seen since Google came into being..but as we all get results depending to a degree upon our localtion, YMMV..
I would say that Google would be likely to say that all TLDs are treated equally, if they didn't say that, no-one would buy any of the new ICANN "fantasy" , "junk" or "shame if someone else bought your brand name in this new TLD"..
Google do not want to "rock the boat"..and there is much money to be made from selling the new TLDs, so those who are able to whisper in Google's corparate ear would wish fror Google to say this.. ;)
Would you buy a dothorse TLD or a dotparis etc if Google said "look guys, these junk domains are just a way to scam defensive registrations out of folks, so we are going to treat them as such, and it is gonna be real hard to rank them"..
Google's friends who are selling these TLDs don't want Google to say that..so Google just said what Google's friends want their customers to hear, so they'll keep buying the new TLDs..
As the British say..."trebles all round , eh chaps" ;)