MxAngel - 1:36 am on Feb 27, 2012 (gmt 0)
It's definitively linked to Twitter, I get that swarm of IP's too as soon as I publish an article and tweet about it.
There's some additional info about the MS IP here:
It has no hostname and seems to go through a local IP range ... I wouldn't make a line for it.
Lucy, 6.0 is Vista
This is mine on a standard Vista / IE8 install:
Useragent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.0.04506)
6.1 for Windows 7
Useragent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0)