You're way behind in versions of OS X which also means you're using an older version of Safari that no longer works with the new MSN. Either switch home pages, update your 10.6.8 and Safari, or switch to another browser such as Chrome or Firefox.
I'm actually experiencing the same thing. I have one computer running OS 10.7…and another computer running OS 10.8. Both computers are updated to the most recent version of Safari available for these OS versions (which is version 6.2…released September 18, 2014). And I'm getting the same message from MSN.com (out-dated browser).
The only newer version of Safari available at the moment is version 7.1…which is only available if running Mavericks (OS 10.9.x). I'm assuming that since the newest version of Safari available for OS 10.7 or 10.8 is Safari 6.2 (and it's not working)…that Safari 7.0/7.1 is what MSN.com needs/wants.
My wife's solution is use Chrome (she likes Chrome)!
But what I don't know is…if the newest version of Chrome (for OS 10.6.8) is compatible with the "new" MSN.com.
p.s. The newest version of Safari for Snow Leopard (OS 10.6.8) is Safari 5.1.10…so an even older version of Safari.
My confusion as well. The max. version of Safari for 10.7 & 10.8 is version 6.2. And the max. version of Safari for 10.6 is 5.1.
I can see MSN.com "orphaning" 10.6 users of Safari…and maybe 10.7 users. But not users of OS 10.8. Basically by requiring Safari 7+…MSN.com is only useable/viewable by Mac Users running 10.9 (currently the newest OS version).
So if you're not on a Mac running 10.9 (Mavericks) and browsing with Safari…then you can't view MSN.com. This certainly leaves a lot of Mac users with older computers out in the cold (or users with newer computers running 10.8). Hopefully Firefox or Chrome has versions that are still compatible with older Mac's…AND compatible with the "new" MSN.com.
p.s. Actually…my wife's MacBook Pro is running OS 10.7.5…and she uses Chrome. So I know this combination works with the new MSN.com.