I see several points in this story which wouldn't really be able to happen, but I give a try to answer rolling with the setup:
Please note, these things clash with real world concepts!
"...what does he really accomplish with that?" Speaking about succesfully making connection between "old-time" and "new-time" internet, information exchange begins. It will create bigger confusion in "old-time", because they are unaware of what has hit them, slowly they will cope with, and data will reach back and forth. As long as "old-time" has effect on "new-time", so long it will prove to be useful. Loosing integrity will make information invalid, and so the connection will become irrelevant on the track of exploiting foresight advantage. Eventually alternative world communication will develop, and both sides will find benefits in having a similar world on the other end. 209
It can span to parallel researching, gray business test sites, these come up for me at first. If <PERSON> has good sense of business (which is not seem to be the case), he can facilitate these possibilities to make good riches and act as an option to have a river of rubies at his weekend island.
"Would it really force them to shut down or would it backfire and make them stronger by providing knowledge of the future and opportunities of trade?"
Depends on you. The concept is so far from real world, bending to your favor will not cause problem.
A) If the parallel existence has close integrity, future will need to manage past derails, and past will rely on future informations. Most commonly I think past will realize a control function above future, and as long as future is not getting fatally manipulated, past will abuse this power. So either future will sieze the altnet connections to prevent harmful events generated by past, or there will be strict regulations to use.
B) If the parallel existence has no integrity, it will be a matter of collective will appearing on the altnets. If many villains turn to altnet to benefit, altnet will have that effect for past, and same from past to future.
I hope this will prove to be a feasible answer for the setup and your question. 824