Whether growing your contact lists, increasing the frequency of current sends, introducing new programs, or ramping up for seasonal events – volume can play a significant part in determining email deliverability.

Sudden spikes in volume can result in short term blocks or bulking as ISPs respond to what can be seen as suspicious behavior from a sender.

What to look out for

Trending the open rates for an ISP is a good way to measure not only engagement with the recipients but also provides a way to identify potential bulking issues:

In the above example we can see the open rates for two similarly sized ISPs trended against the weekly send volumes. ISP1 shows a significant drop in open rates as the volumes spike in week four, if the increase in volume is not from sending to disengaged or unfamiliar audience segments then such an unusually low open rate is likely to indicate bulking at the ISP, as a direct response to the sudden volume spike. 

Comparing the trends to similarly sized ISPs (ISP2) can also help to confirm these issues, as we can see with ISP2 there is a slight upward trend during week four, an opposite trend to ISP1, suggesting that ISP1 may be more sensitive to these sudden increase in volume and so more likely to react to them.

What to do

1)    Start early – if you’re ramping up for the holidays or any other seasonal events start to increase your volume on the run up to the event so that on the day you want to send to the new volume you’ve already reached this goal safely. Some form or ramp-up plan should be followed to help ensure the daily/weekly rates are safe and will not result in adverse reactions from ISPs.

2)    Protect your regular sends – If part of your volume increase is to include older segment groups, plan your sends so that the regular news letters are not impacted by these older groups who are more likely to complain or generate unknown user bounces.

3)    Discuss with us – For any significant increases in volume talk to us! We can help review the volumes you are planning to hit and advise if there are any risks with the increases. We can also advise if there is a need for a ramp up plan to be created specifically for your sends.

Remember growth is good! but planned growth that doesn’t impact existing performance is much better!