We've found the ideal number of partners in a high-quality giveaway is somewhere between four and seven, for this reason we’ve capped the amount of partners allowed in a sweepstakes on DojoMojo at eight.
The reason for this is that during a campaign, each partner receives all the email addresses as entrants come in. This means that all partners will be sending email communications to the entrants. The new subscribers are much more likely to feel frustrated after receiving 10+ welcome emails in a short period of time, as it feels like spam.
To counteract this, we encourage campaigns to have fewer partners so that new subscribers are less likely to feel bombarded with a flood of emails and as a result, are much more likely to open your's. This has also shown to lower unsubscribe rates and increase conversions.