I just noticed a large number of guests on the forum, around 70... we tend to have about 30 for this, and when it 'pops' I tend to look into traffic sources to see if there is a link/tweet or something to boost it. When I looked in google analytics, I got a completely different number..
Anyone else experience this and know which might be right?
In addition to the above, Google Analytics is showing you current visitors in real-time (ie users that have your website open and focused).
The online status in XenForo is measured differently, using a timeout (defaulting to 15 mins) from last activity. So that means you have had 70ish "guests" in a rolling 15 minute period, not all at once.