Custom makers are too busy to hang out on forums much.
I've been BUYING customs for less than a year and currently/have owned about a dozen or so. So, here's a custom newbie's take on it...
The forums are a GREAT place to find out about NEW custom makers that are just starting up, still work cheap - you can get NICE knives at great prices that way and I'm always watching the forums for new and/or lesser known makers.
I'll ALWAYS look for a maker's website, and if he has one there's a better chance I'll order. Not just so I can look at the knives he's done in a gallery, but also get a feel for the maker and some information about him, his methods, how busy he is, if he'll work with you on options... so INFO or a little BIO on a website is a good thing.
I think reputation on the forums is a pretty BAD measure of a maker. Problems tend to MUSHROOM when they're posted on a forum. I've had quite a few less-than-positive experiences with makers but I don't post them because I know what will happen. It'll SNOWBALL and something that was an irritation for me will end up ruining someone and probably make me look like a jerk in the process, so I keep my mouth shut and just don't order from them anymore. But I WILL share that info one-on-one with people I know.
I have also seen very positive reviews of someone's work on the forums, but when I contacted the maker I felt like the maker must have thought he was a movie star or something because he couldn't take 3 minutes out of his day to give me more than a one-sentence reply to a very flattering email I had sent him along with a few questions.
The BEST thing is to talk to other people by email who have worked with a maker before - especially people you know. Obviously, you meet those people on forums and I have had GREAT luck hooking up with marvelous knife makers and even making friends of some of them this way. I've also been warned about people from people I know when no warning could be found on the forum. It's not a perfect system. I was once lead astray by someone I knew and trusted and lost hundreds of dollars to a maker who my buddy had had a good experience with.
I think the best reason for a maker to participate on the forums is the benefit of receiving the feedback of people actually talking about his knives.
For the MAKER the best thing is word-of-mouth. Treat your buyers like you'd treat your own mother and they'll say nice things about you more than you know and become return customers.