Our company sends our only three promotional emails each year Oct, Nov, Dec. For the last few years here on Campaign Monitor we've have a relatively low rate of being flagged as spam. Low enough I'd assume it was end user error-- flagging us as spam instead of unsubscribing.
For the past three years the few spam reports we received appeared essentially in real-time. Within a few minutes of sending the campaign we'd have one... and another one or two later in the day. We'd only see them on the first day of the campaign being sent (and only a couple).
Our first campaign for this year went out Oct 29th. I was giddy that days after we sent it there wasn't a single spam report... until today. We just got slammed 15 days later with an unusually high spam complaints-- all showing up this morning.
As we're only seasonal emailers... did we miss something over the past year? I'm really shocked at how high our spam complaints are-- and why they would all happen today between 5am and 10am this morning, so long after the campaign was sent. We didn't even have any HTML opens today... and we haven't had any noticeable HTML opens since Nov 6th. Is there now a delay in spam reporting?
Sometimes spam reporting does happen in batches, depending on how busy the systems are. In that case, the complaints are captured as the come in, but processed all at once and inserted into your reports.