Regarding requiring a log in to read only, this is one of the only forums I visit that requires a log in. Generally, if a forum requires a log in just to try it, I move on - just a personal thing. Generally, in developing a web site, every click and action that a site requires to gain access results in lost users. Require a simple click, lose users, require entering info, even more lost users, require a log in, even greater lost potential users. One ends up paring a potential user base before even exposing them to the forum.
Also, the last ratio that I can recall, is that typically, forum users that simply read (lurkers) vs. those that post, is about 10 to 1. Personally I see nothing wrong with those that just read - each user that is just reading becomes that much more likely to eventually participate. For our forum, some folks may not be as immersed in 968's as others, but none-the-less have a high interest, and visit on occasion. Making the forum as accessible as possible sets the stage for a more vibrant forum long term.
Also, another idea to dismantle barriers to participation, ie: unnecessary clicks, would be to have 968forums.com point directly to the forum main page. For example the landing page could be what is now 968forums.com/index.php. See 924board.org. If one types in that address, they are in the forum directly. The easier things are, the more usage and more frequently visitors visit.
Regarding bots and spam, I am not sure what bots coming are terribly bad, as long as tools are in place to prevent automated posts and a log in should be required before one can post. Obviously one should not post an email address in a post that is in an easily recognizable format. Most bots coming are generally good, because they are looking at site content to populate the search engines that are the source of new users/members. There are exceptions, but the benefits generally outweigh the negatives.
One thing to remember, is that any person who posts, was once only a reader. Readers are the well for members. For the most part, readers are here for a reason, they have an interest in the forum. The process is generally for folks to first check things out and get comfortable with the community before signing up and posting.
Regarding tracking, one can analyze many aspects of usage whether someone is logged in or not - there are lots of tools for this - Google Analytics, 3DStats is great, other tools. One might want to do a test and track the bounce rate for new visitors - with reading allowed without signing in, and with signing in - my guess is that the bounce rate would be noticeably reduced if sign up were waived to read only. Might also consider a test of making the forum main page the home page and see the bounce rate there - and also measure forum activity with the home page landing one directly in the forum. No way of knowing for sure what would happen, but there is a good case it could be beneficial.
Just a few ideas based on some years of experience. Love the forum.
Alas, someone buying a first round is always a welcome incentive :-) however likely not going to make the Paso Robles run as I'll likely be east (where I get to fool with my 931 back there) but hopefully some upcoming SoCal gathering in the near future.
Also, please excuse me for just dropping in after not having visited frequently for a while and suggesting a bunch of things - just thought some of those mentioned might have actually effected my own visiting frequency.