More and more Facebook users are accessing the network via mobile these days – and that fact is key to Facebook’s growth (both in sheer volume and in terms or revenue). But a new report from PageLever suggests that page owners need to take a closer look at mobile promotion, as more fans are now coming from mobile than ever before.

According to the study, which looked at over 500 different pages with at least 100,000 likes, 19% of new fans were coming via mobile in the month of August. That’s compared to only 5% coming from mobile in May.

“Rather than just measuring “mobile fans,” I measured “mobile-fans-per-total-fans” to make sure these numbers weren’t affected by fluctuations in overall fan growth.

It’s not clear to me why this jumped so fast. Facebook may be attributing fans who come from ads targeted at mobile as “mobile” rather than “ads” but I’m not sure and their documentation is slightly ambiguous,” says PageLever. But the fact remains, mobile likes are growing whether it comes organically or from mobile ads.

What could be driving this influx in mobile-generated likes? Well, Facebook’s mobile-only ad product could be the reason. Back in June, Facebook gave marketers the option to target Sponsored Stories to mobile news feeds only. Before, advertisers couldn’t specify exactly where they wanted their Sponsored Stories to appear. Facebook also unveiled Promoted Posts for pages, but this works the same on both mobile and desktop.

Earlier this summer, Facebook also unveiled a giant like button that spans the entire bottom section of posts from pages on mobile. Now, when you see certain posts in your news feed on mobile, you can like the page without having to navigate to the page itself. This could also be a driving force in the spike in fans coming via mobile.

[h/t Mashable]