I am having the same problem–eMessenger works (have sent IMs to myself) for MSN Messenger but neither MSN Web Messenger nor Yahoo! Web Messenger work. I even tried Hopster but that didn’t work either (says all ports blocked).

Our Internet access is through an ICA Client and Windows Terminal Server. Are there other rules for this kind of access? Or is this common? I do not want to ask the network admin. which port to use or how to bypass the firewall (duh!).

I keep looking for the Yahoo! equivalent to eMessenger. No luck YET.

If anyone has any tips until a third-party Yahoo! webmessenger solution comes around I would be grateful.