Expertise

First impressions are everything! Whether it be face to face or through an online forum the presentation and first few moments of interaction or engagement usually give me a good inkling of what to expect should the relationship move forward.  In terms of the web visual appeal is going to weigh heavily on how reliable or credible I find a site to be.  Now just because it is visually appealing doesn't necessarily mean the information or materials published are in fact accurate or proven but if it is professionally displayed in a creative way I tend to be more engaged and drawn in to learn more.  I usually look for other contributors to a site for validation of the materials presented by the site owner.  I also look to see if they are referred by other sites and those in similar fields.  I don't think I treat online forums that differently from face-to-face other than first and foremost I would obviously vouch for a face-to-face meeting any day over the web, but I actually rely on the web for quite a bit and most of research stems from my daily google searches.  If I am questionable about a specific topic I usually try to research multiple sites to make sure I'm collecting information that is going to be useful to me.  I also tend to notice sites that have large name vendors or businesses advertising on sites.