Strange behavior (ajax long-polling channel) "refuses" connection from normal browser?

When you copy this link

http://q55.queue.vkontakte.ru/im639

and place it to currect browser tab, press enter, it does "load", address changes, but content is still the same (you're still in this question). What's that? Is that programmatical behavior ?

I am not seeing anything. It does not do anything because nothing is available.

alfred@alfred-laptop:~/node/contact$ curl -v http://q55.queue.vkontakte.ru/im639* About to connect() to q55.queue.vkontakte.ru port 80 (#0)
*   Trying 87.240.134.232... connected
* Connected to q55.queue.vkontakte.ru (87.240.134.232) port 80 (#0)
> GET /im639 HTTP/1.1
> User-Agent: curl/7.21.0 (i686-pc-linux-gnu) libcurl/7.21.0 OpenSSL/0.9.8o zlib/1.2.3.4 libidn/1.18
> Host: q55.queue.vkontakte.ru
> Accept: */*
> 
< HTTP/1.1 204 No Content
< Server: nginx/0.7.59
< Date: Mon, 11 Jul 2011 18:49:25 GMT
< Content-Type: text/html
< Connection: keep-alive
< 
* Connection #0 to host q55.queue.vkontakte.ru left intact
* Closing connection #0

We get status code HTTP/1.1 204 No Content

Also this has nothing to do with long-polling, because the connection is not hanging at all. It looks like the URL is pointing to an image. I can not image you should be doing long-polling for retrieving a simple image.

The server responds with a 204. See here which explains that on a 204 server response:

If the client is a user agent, it SHOULD NOT change its document view from that which caused the request to be sent.