Special interests ?

Could someone explain to me what defines special interests ? How is it different from hobbies?

I don't think I have special interests but will explain what I do do.

For years I have been frequently checking my rss feeds and later Twitter for articles to post on forums. These are primarily mental health related and secondarily political and general articles .

I also save many of these articles to my usb drive .

Whilst thinking this does not qualify as special interests I have a feeling it is not typical NT behaviour either.