My short answer is that as long as the recommendation is appropriate for the question asked, who cares what the motivation behind the suggestion is. The answer will be helpful to those reading regardless of who the poster might be friends with.
As for my long answer...personally, I think this board is way over-moderated. I'm not a WAHM, but I do deisgn and make diapers for Ben just for fun so I have an idea what these WAHMs put into their products. I'm also in direct sales (not diapers), and the key to sales is filling a need. Selling something they don't need is unethical, in my opinion, but selling something that meets a need is just as honorable as buying. With that said, I many times feel bad for the WAHMs because the rules are so strict. If someone asks for a good nighttime diaper and you've spent hours designing one that works for you and has some unique features in comparison to others on the market, you ought to be able to say "I sell product X that might meet your needs because it ----." Personally, I like recommendations from people who have used certain diapers, but if someone designed a diaper to work a certain way, I really pay attention. Take Little Lounging Lizards, for example. She states on her website that her diapers are very absorbant and trim and she shows how she designed them to be that way. As someone who sews and has tried making diapers, I have a lot of respect for that. If I asked about nighttime diapering, I would want to hear recommendations from both users and designers explaining why their diaper might work for me. The more educated I am about a product, the more confident I can feel when I buy it. Not all diapers work for all babies, so there is going to be more than one answer for any given question. Perhaps I'm that way because I want to know WHY something works well rather than just a blank recommendation (i.e. 9 layers of hemp when tri-folded vs. very absorbant diaper). If I were a diaper-selling WAHM, I don't know if I would surf this board because I would have worked really hard to design my products but here I would feel like I have tape over my mouth. In my personal business (direct sales), I do not advertise - I just work with friends of my customers and so forth and I never run out of people to work with. This board, IMO, should be a place where mothers discuss diapers and how they work on their babies - simply mother to mother. It shouldn't matter if you have a baby who just uses diapers that other people make or if you use diapers your design yourself. As long as your suggestions are reasonable solutions to someone's problem, it doesn't matter if you're recommending something you make and sell or just something you've bought and used.
I'm probably really going out on a limb to say this, but sometimes I think that the diapering board should not be the "MDC Diapering Board" but rather the "WAHM Diapering Board" since all administrative decisions revolve around how the board can best benefit those who choose to advertise here. If you're on the diapering board, you'd better discuss WAHM-made diapers. We use diapers I have made, but in the process of making them, I've tried many diapers. So the diapers I recommend are based on my experience with the one I have used. But I can only speak in terms of those WAHM diapers we have tried, not the ones we actually use. Thus I always have to think outside the box and recommend products that I've found which are similar to the ones I've designed in order to help people. I can't say that I've made diapers even with pattern X that work well for us - I have to refer to them as though I bought them from a WAHM. Otherwise I might be "promoting myself" which I am not, and in implying that I bought them from someone else, I'm promoting businesses that sell those diapers. Granted, most moms are not going to make their own diapers, but many WAHMs do custom orders, so if you asked for x layers of hemp, you could probably get it.
Simply put, I think this board is a little too concerned with protecting its sources of revenue, with this whole discussion as a great case in point. Trying to read people's minds and determine whether or not they're spamming for someone they know is simply way too controlling, IMO. Let people talk freely. I know that advertising provides revenue that makes this board possible, but if you are too controlling about what is said and what isn't, the board ceases to be a pleasant place to visit, and thus devalues the advertising done here since less people are coming to the boards. And if you have too much advertising, that gets annoying too. Personally, I click on banners all the time. But I never click on signatures or on ads on that page before you get to the diapering board. Quite frankly, I find that page before you get to the diapering board far more annoying that I would find a WAHM saying "I designed and sell diaper X that might work for you because it has X, X, and X." Again, yes, money talks, but if you start to annoy people with your advertising and become too protective of those who advertise by making strict rules about what can and cannot be said, people will quit visiting your site because it just ain't fun anymore.