I amsterdam is Amsterdam city council's promotional logo.
To quote from the website: I amsterdam is the motto that creates the brand for the city and people of Amsterdam. In saying or expressing I amsterdam, we demonstrate a clear choice for the city of Amsterdam. I amsterdam shows our pride, our confidence and our dedication. I amsterdam is our personal endorsement for our city. Using I amsterdam, we can show clearly and proudly all the many benefits, opportunities and dimensions of excellence that make Amsterdam our city of choice.'
The website has lots of promotional information and puffery about how fabulous the city is to do business in and all the usual stuff about museums and the like. Scheduled for a major overhaul towards the end of 2008.