Checking rankings is part of the puzzle when it comes to measuring your organic performance. Whilst there are many factors that may affect ranking performance, localisation, cookies, signed into Google etc., we won’t go into the specifics here.
Either way, you still need to benchmark and most importantly you need to be consistent.
Ever since Google changed over to SSL, you may have noted a new operator appended when going to http://www.google.co.uk, for example, you’ll probably get this now (in Firefox at least):
Google Web Server Redirect &gws_rd
This is effectively the Google webserver redirect to the SSL version. In the UK over the last few days, Google appears to be using this to redirect on a country level also.
Country specific checking – &gl
In the past you could check country specific results by appending the &gl geo-targeting tag. Web queries like this were used to check unpersonalised country specific results:
That would have served US results for those in the UK (well, as much as possible). If you used this now in UK you would be redirected to google.co.uk serving UK results even though &gl=us was used.
The rise of &gws_rd = cr
To stop this from happening, you need to append a new operator &gws_rd=cr
This seems to happen on the Google.com only for now but could be rolled out worldwide later.
So if you’re seeing huge fluctuation in results, check this first.