Why are all my websites thinking I'm in New York all of a sudden?

Every major website I go to is giving me banner ads for NY Knicks season tickets, The Straight Dope included. When I go to MSN it gives me the weather forecast for Rochester.

My ISP is in Colorado and when I am on the work VPN it is in Washington, D.C.

I am tempted to go to a NWS site to see where the hot girls that want to meet me are from.

Check your apartment just to be sure you haven’t moved. If you aren’t actually in New York…

<WAG alert>

My impression is that these places that localise ads and content to the browser’s location are going by the browser’s computer’s IP address. Maybe your ISP has just gotten a new range of dynamic IP addresses that formerly belonged to a New York ISP. Has your ISP bought anyone out recently?

Might be likely OP is using DSL? I’ve found that DSL IP blocks are much more generalized than cable modem blocks. When I’m at the office and using TimeWarner, the ads on the image hosts know the particular part of Los Angeles I’m in, whereas when I’m at home on AT&T DSL they only know I’m from Los Angeles and do not get any more specific than that.

I’m on Comcast cable. The weird thing is that normally when I’m on the VPN I get ads from DC, and when I’m off I get very localised stuff near my home. Now it doesn’t matter if I’m on or off, I get NY.