Come on,

Where are Hikkis supposed to socialize if it isn't the net?

Hikkis live on the net. Their Computers are their lives.

And while technically, it may be considered false to call a non-Japanese NEET who has no friends and stays in his/her room all day a hikikomori, I think it's permissable, especially since the phenomenon is not unique to Japan, but most modern, post-industrial nations, although its symptoms are probably more easily cultivated in Japan's particular, non-confrontational culture.