The way we have it configured here at SF is as follows:
Active Members Time Cut-Off
Enter a number of days here that represents a threshold for 'active' members. If a user has visited the board within the past number of days you specify, they are considered 'active'.
Our value is 30 days but any other forum using vbulletin can change it to whatever they want.
So only 31 people (who are logged in) visit this site per month?!? Seems low, but perhaps people are not bothering to log in. So site usage is very unlikely to be the cause of the occasional slow performance or internet server errors.
Yeah that doesn't tell the entire story. There are plenty who don't log in and also thousands of denied spam registration attempts. There is also lots of traffic from spiders over the month. This server also hosts more than just this site. All combined though, it shouldn't be so much to cause us performance problems like this. I need to really spend some time figuring out where the problems are.