Robert posts about having to use more than one MSN Messenger account due to limits placed on the service as far as number of contacts you can have on one Messenger passport account. He has to use two computers in order to work with two instances of messenger.
I have the same problem (multiple personalities, that is, but for different reasons than Scoble ), and I am not personally interested in Trillion or other IM interfaces for this purpose, and I Already use Windows messenger for SIP service at work, so I don't want to go there.
It turns out it is possible to run two copies of MSN messenger with different accounts on the same computer at the same time. It used to be that you had to alter the messenger code to do so with a third-party program, which is not allowed under the software license. But more recently there is a program available that starts messenger and acts as a sort of proxy, so you're not (AFAIK - I will promptly remove this if I am wrong, of course...) in violation of the MSN Messenger software agreement, which specifically says you can't modify the MSFT binaries.
It also starts up in "appear off-line" state by default, which for some people is helpful. It's not a perfect program, but it works pretty darned well.
JnrzLoader 6.2.0137 is the program name, and it is available to download from http://www.mess.be (along with a lot of other nifty stuff).
Of course this advice is totally without warranty, your mileage may vary, scan your files, yada yada. But it works for me. :)