I think USCIS is trying to fix one common misuse by certain applicants where he /she applies for H1B through more than one employers ( typically body shop companies) and tries to increase his\her odds of getting the visa. Sometimes the applicant gets more than one H1B visa and wasting the limited visas.
You can get one chance per applicant now. So if 10 companies apply for you, the chance of being selected is the same as if only 1 company apply for you.
It used to be much more expensive to make an H1B petition so this strategy was not viable. Then they made it way cheaper, leading to the mass applications.
yeah, I've heard a bit about this- basically, it is technically legal right now to have multiple job offers from separate employers to get multiple H1B lottery tickets. The abuse comes from some shady operations, that will basically give you 3-10 "offers" from various consulting firms, where you'll be paid way less than market rate to work at any of them, with the idea being if you win a ticket from any then you trade off your potential salary for the H1b.