MERB has 5 times more activity, so for the best return on advertising money, there should not any hesitation, MERB is #1.
People make a mistake when they're comparing the two. Comparing Mer(c) to Merb is like comparing the Saskatchewan Roughriders to the Dallas Cowboys. There's no comparison. But considering the amount of references made to this board from the various active posters of that particular board, it's not that surprising to see people compare the two boards. As long as its members continue making references to this board, it will always continue to be known as Merb's illegitimate little brother (or sister).
It's my personal feeling that Mer(c) will never be taken seriously as long as this is the case. Any mention of its big brother (Merb) will always bring about comparisons, which is the last thing Mer(c) should want. It actually makes Merb much bigger than it actually is. And for Merb's operator, it's a great bonus since it brings up the value of his board.
I also can't think of a single reason why Mer(c) would deserve to be more popular than Merb. It's simply not an interesting website to surf to & the amount of information it provides the avid hobbyist is very poor. A lot of the stuff is either already available elsewhere or totally made up or grossly exaggerated. Gossiping has basically taken over the board & it can no longer be used for reference purposes. It reminds me a lot of the Fox News (a.k.a. Fake News) right-wing propaganda network. I suppose advertisers have their own reasons to advertise on it. Personally, considering the amount of hits it gets (as compared to other sites) & its low membership, i also cannot fathom why. However, it's not my money & the advertisers can do what they want with their hard-earned dollars.
My guess is that considering their huge differences, both boards can easily co-exist with one another. The amount it costs to operate Merc(c) is extremely small as compared to the amount of advertising money it helps to bring in (along with the other sites the operator has). There is no financial reason for the operator to ever want to close it down since it basically pays for itself....and more.