Retailer infatuation with Pinterest is not a new phenomenon. Of the many companies embracing the hot image-based social network, retailers, for obvious reasons, quickly saw the potential to promote their wares.

Just how much are retailers investing in Pinterest? According to a new study by Responsys, major retailers have been making Pinterest a focal point of their email marketing campaigns this year.

Since mid-February, Responsys has seen more than 55% of major retailers promoting their Pinterest presences using email. Pinboards are the most-promoted Pinterest assets, with 53% of retailers highlighting theirs to subscribers. 17% have also promoted a Pinterest-based contest, while 6% have added Pin It sharing links to their emails.

A trend with momentum

Responsys expects that retailers will soon wrap up the bulk of their work on building a Pinterest presence as they gear up for the holiday shopping season. On that note, the firm sees 65% of major retailers implementing holiday messaging in their email campaigns by the end of this month.

But a focus on driving sales during the most important retail quarter of the year doesn’t mean that Pinterest won’t play a role in retailers’ marketing strategies in the coming months. To the contrary: Chad White, Responsys’ lead researcher, expects to see some retailers use the holiday shopping season as an opportunity to experiment with Pinterest promotions.

“Since this is retailers’ first holiday season with Pinterest, we expect to see some interesting experimentation over the course of the holiday season, most notably with wish list-type pinboard sweepstakes,” he stated.

All-in, or wait-and-see?

The big question for retailers, of course, is just how much effort they make to leverage Pinterest’s popularity. Despite the evidence that Pinterest may be a far more productive social channel for sales than, say, Facebook, the startup’s monetization plans are still largely yet to be established.

That’s good in some ways — retailers are largely free to experiment without butting heads with Pinterest right now, or paying the startup — but it also means that there’s uncertainty about what will be permitted in the future. As we saw with Facebook, for instance, the rules can change and retailers turning to Pinterest this holiday season should not assume that what they do this year will be possible next year.