About 30K posts on my forum are in private buy/sell areas. We have it set so certain usergroups don't have access to the forum including unregistered users, which bots would fall into. I am wondering is there anyway to get bots to index these pages, i.e show title and description. Then when a user clicks, tell them they don't have access, and to register. I think this would help boost registrations. I thought I remembered there was a way to assign a login to spiders, but I don't know how to do this with vbulletin. Please help. Thanks.
That would be called cloaking, showing info to bots that guest can't see, and will get you penalized if google catches on.