Regarding GDI, all it is is an MLM (a pretty shitty one). You're selling people like $1/mo worth of hosting and a worthless domain for $10/mo and the only thing to excite them is the prospect that they can then sell it to other people who can sell it to other people etc. Typical pyramid scheme trying to hook losers who don't know any better.
They've been flooding Twitter with their spam for eons now.