Fandom - push technology meets plugs

I got this in the mail a few days ago (to my soon to be abandoned hotmail address, which is clogged with penis enlargement ads. Consider it - M$ gives you only 2MB storage while average spam item is 136K!).

Dear Friends,

My new Harry Potter fanfic has begun to be posted at the Sugar Quill. It's called "[snip]" and you can access my author page there at the address [snip].

You are on this mailing list because you made a positive comment about one of my previous stories ([snip], [snip] or [snip]). I will remove your name from the list on request.

Best regards,

[snip]

So, is this spam payback for being a good reader and leaving a signed review? Or is this a legitimate service I should be thankful for? Personally, I like to subscribe to updates myself, and many authors use Yahoo! Groups exactly for this purpose.