Don't agonize over day-to-day earnings.
I wish I had a Dollar for everytime someone wrote that here!
A part-title of this thread is "observations" and whilst earnings for some may fluctuately wildly there are some of us who have very consistent daily metrics and when one suddenly becomes out of whack, e.g. a 50% reduction in CTR as I was hit last May 6th, then we post our observations.
Agreed there's nothing we can do about it but when ONE day's observation turns into 9 month consistent trend then it is worth posting.
Obviously there can also be other reasons, for instance a few months ago I found out I had an overnight server outage of several hours simply because of much lower than average daily earnings.
A couple of days ago my CTR was way up yet my EPC was massively reduced, why? Some nice South Korean decided it was a great time to click on my sites and 50% of my daily, yes daily, clicks were from Korea at USD 0.03 EPC.
Honestly, we come here to moan amongst erstwhile colleagues since many of us work alone, my Husky doesn't understand, my wife doesn't care and I like ramblin' on ... Courtesy of Led Zeppelin:-)