I was just browsing through the the unread posts and noticed there was 8 members online and 61 guest's. I guess I don't really want to know who they are but why there is so many that read the posts but never ask questions. Or are they real? Could some of them be bots roaming looking for email addresses ?

I would guess mostly bot.  Anyone can buy the software: https://webmasters.stackexchange.com/questions/3588/how-do-spambots-work

Maybe anyone browsing the forum without being logged in appears as a guest? I'm thinking it could be legitimate members that simply hasn't signed in. I often browse the forum without going through the exercise of logging in... It's easier.

I only log in when I have something to say.

I'm logged in automatically, something to d with cookies.

You may be right on the guest. I basically never log out...