Yahoo has the most annoying indexing robots/spiders in the planet. These crawl the site and index it for their search engine. Unfortunately once they find a site they can send up to hundreds at a time. Hence the /most online' count keeps spiking ever upwards -- it says *645* now! -- and it can look like we are flooded with guests. This has been a plague for lots of boards for ages I have learned; I have just never had this one indexed so intently. It is good to be indexed of course and makes it easier for people to find say an article of interest, but I don;t much care to have them all online in their hundreds every day.
I have plenty of bandwidth and capacity so that side of things doesn't matter but having so many at once online is pretty obnoxious so I've written a little file that instructs Yahho robots to only be allowed every 30 seconds, one by one, on the site. However this can take up to a week to take effect so you may continue to see large numbers online.
This is just a claification for anyone who has wondered what the heck is going on with floods of guests!