Just looked at:

http://www.koptalk.org/forums/online.php?Cat=0

and there are hundreds of IP addresses that are very similar e.g. 66.196.90.* 66.196.91* as guests. What's that all about then? Most of the 'last on' times are tomorrow's dates and times also

I used www.samspade.org and entered those IPs, they are Yahoo spiders.

I almost always have between 3-5 spiders of some sort on my site.

https://www.ubbdev.com/forum/showflat.php/Number/116294 might be useful for you to show a bit more info

Has anyone seen a difference with spiders with the upgrade? I started seeing anywhere from 5 to 10 everyday but since the upgrade to 6.5 I barley even see 1. I do have the spider friendly urls selected and I alos made sure the robots.txt file was there...

They are completely periodic and seemingly random. I have 5 on my board right now. Sometimes I will have 1 or 2, I have had as much as 30+.