I really think this is a bad idea. Every other site I've become a member on had/ got a membership feature. And every time the same thing happens. Suddenly, because of the special forums, privileges, etc., If you don't/cant pay for membership, its not really as fun anymore. All the older members who are more devoted to the either can buy membership or have it donated by adoring fans, so all the "cool people" get membership. Then all the new people decide the best way for them to get started and be recognized is to buy membership, because that's what all the older members have. So the members forum gets spammed up with stupid people (NOTE: I didn't say "new people" here, as most new members to Instructables actually have a neuron to fire. But the ones who feel they really need to buy membership to get people to recognize them are usually the dumb ones) who cant post their bug topics or "AMAZING AIM CONVO !!1!!" to the "mere mortals" section, and the members forum begins to get annoying. At the same time, the other forums are full of people who want membership begging for it however they can, complaining about it, etc., because they all think that its awesome to be pro. Of course, none of the pro users will admit that its starting to suck, so people finally get it from someone so that they will finally stop begging or break down and BUY it, get access, and after a few hours, agree with the other pro members. Of course, now they can brag and act godly around normal members because they have a stupid badge/colored name/other member benefits. I'm not saying that this will happen to Instructables necessarily, as the membership comes with other benefits besides forum access. But it will have side effects, just look at all the protesters already. Instead, I would just have a donate button (With some thing like a badge, but no real benefits. Most people would donate just to keep this site running.), coupled with new merchandise in the store and more advertising for the store. You can order wristbands printed with custom words and images to sell, hold design and product contests, sell "Instructables" kits with the parts for popular Instructables (giving a cut to the authors, of course). All said, I don't think this pro thing is a good idea. It might work, but its too much of a deterrent (in my humble opionion), when you charge for half of a free show and tell.