Title says it all.

Hell no.

Encouraged but not required. If you make an account on both sites and then submit your run to both, it's less work for the moderators. They'll want to make sure the two boards are as mirrored as possible for maximum accuracy. If you only submit to one site or the other, they'll verify your run and then submit it to the other on your behalf. You'd be doing them a favor by doing both submissions on your own.

As of right now, it seems as if my comment from 10 months ago is incorrect. The current moderators seem not to want to verify runs on this website unless those same runs have also been submitted/verified on MMLB, so make an account on both sites if you intend to have your runs on here.