I just updated to the latest version of the MSN Search Toolbar. There seems to be some discrepancy over the version number. It’s called Version 1.2 in some places; version 2.0 in others.
In any case, the new version adds tabs to IE–so you can browse to multiple sites yet stay within the same IE window. I’m still not sure how useful the interface is, but many users have been requesting this feature for some time now–so it must have some merit.
I find the "Open each link in a new background tab" feature useful; it saves me from having to right-click on hyperlinks and select "Open in New Window". I’ve also noticed a few issues with misbehaving sites that seem to insist on wanting to open up their own browser instance.
IMO, the MSN Search Toolbar has made remarkable improvement as of late. When the first beta was released, it had plenty of quirks; now, however, it seems like a very solid product.