The email you got, was because someone wants to contact you on msn. They input your email address, and you werent available as a msn account, so they sent u an email about it.
Others who currently use msn may have received an email in regards to Windows Messenger Live.
I have used this and find it sluggish even with 512mb of ram and a relatively new pc. You can roll back pretty easily from windows live to windows 7.5 *i think*.
Its green, works alot like windows xp in terms of flash scrolling menus etc. Pain in the rear for me, I just want to talkt o my friends and find them easy.
Both emails are legit, as to whether or not the people are? Can't say.