Question about mass link indexers – how do they work?

Hi all,

A complementary question about indexers: I've always wondered how they work. I'm not talking about indexers that send their link directly to Google with a proxy, I wonder more about the massive indexers like EliteIndexer and ExpressIndexer (these are the only ones I know)

So, does anyone know how they work? Do they create crap T2 links or do they have another form of indexing? These are massive indexing services, so I guess it's pretty spam.

Someone knows?

P.S.: Also ask sideways, do you think they really work? I never really used them, but I'm considering it.

Thank you