In certain circles this is probably common knowledge, but my mind has been blown away by the fact that you can browse to a site just the once and Google will remember and potentially favour that site in future results.
I was chatting to Barry Adams today about how different country specific google pages list results depending on if you are visiting the site from inside the country versus outside. So if I visit google.fr whilst sitting in Belfast do I get a different experience than if I was visiting from say Paris.
An interesting use case appeared to crop up where if you search for our company - Pierce Communications on google.com we rank top, which is odd considering there are other US based companies called Pierce Communications. Initially we thought it was because Google was remembering our searches, so I tried on a different browser and Barry asked some US friends of his to google the same.
Initially it looked like we were indeed top, but later we found out that the person involved was signed into google+ at the time and had visited the pierce site before.
For better or for worse Google attempts to match the sites it thinks you personally want to see instead of giving you the more natural order that a complete new comer would get.
This raises all sorts of questions, but the one thing that is bothering me the most is now how crucial that first contact with a potential site user is, if you can get someone to your site at least once, there is a chance it will affect how often they will see your website in the future in search results.
By virtue of the fact you are reading this means the next time you type in something totally unrelated to this article there is a chance my site will appear higher in your rankings (thanks, by the way!)
There used to be this notion that traffic from things like delicious wasn't valued because you would get the spike and nothing more would come of it, but now could this mean that if you can get those people onto your site the once they are more likely to visit it again at a later date?