The Twitter-owned microvideo service Vine has had better days. Earlier, Marketing Land revealed that user sharing of six-second Vine videos plummeted after Instagram debuted a competing service last week. But Vine isn't Internet roadkill quite yet.

Marketing Land conjured data from Twitter-metric firm Topsy, comparing how many times people shared instagram.com links on Twitter against the frequency of vine.co links. Its most stunning revelation: Sharing of Vine videos dropped by almost 40% on June 20, the day Instagram launched its video service. So far, there's no turnaround in sight.

Some other notable findings:

  • On June 15, users shared almost 3 million Vine links.
  • On June 19, Topsy reported 2.5 million shares of Vine videos.
  • On June 20, that figured plunged to 1.5 million.
  • On June 27, Vine sharing dipped below 900,000.

Instagram sharing on Twitter has also edged up as Vine's has waned, according to the Topsy data. Instagram sharing spiked by almost 250,000 links—a 17% jump —on June 20. Once that surge dissipated, Instagram sharing fell back significantly, but remained at a level slightly higher than the service had seen for much of the previous month. 

Another telling way of thinking about all this: As of yesterday, users were sharing twice as many Instagram links as Vine links, whereas on June 15 the reverse was true. (Recall that Instagram sharing includes photos—Instagram's mainstay prior to June 20—as well as video.)

Twitter, which hadn't responded to my request for comment as of publication, is clearly aware of Vine's predicament. Just this morning, in fact, Twitter sent out a mass email promoting Vine this morning—almost as if the company was eager to rekindle the interest of users who might be tempted away by Instagram.

(See Twitter's Vine promo below and to the right.)

Where Vine Goes From Here

Although Twitter released Vine for Android earlier this month and recently added support for the front-facing camera, those moves clearly haven't been enough to retain user interest over the past week. 

The first thing Vine can do? Don't panic. 

"Instagram still has the novelty factor," social media strategist Mari Smith told me. "All [Vine] may need to do is stay the course."

Technology in general—and social media in particular—is a tumultuous industry. If companies freaked out every time the metrics rose or fell, heart attacks would be the new rite of passage for Silicon Valley execs.

Twitter CEO Dick Costolo seems to have taken that advice to heart. On Wednesday, he told an audience in Washington that he's not worried about competition from Instagram:

Other people can replicate that or take pieces of it if that’s what they want to do.... If we do what we want to do, and go where we want to go, we don’t have to worry about what that guy’s doing over there.

Vine, though, could definitely use a dramatic move to recapture the initiative. Twitter has already tipped that it has some "exciting new parts of Vine" to announce this summer. That's a good start; the stakes for that rollout are now considerably higher than they were just two weeks ago.

Whatever Twitter does, it's now clear that it is really at war with Facebook. Both services are vying to establish themselves as preeminent repositories, or "sinks," for the vast numbers of photos, video and status updates their users generate.

(See also Twitter's Vine App Officially Comes To Android)

And they're getting increasingly petty about inconveniencing their own users when it suits their business interests. Twitter, for instance, will display Vine videos directly within tweets, but forces users to click away to see Instagram video. Facebook, coincidentally enough, plays Instagram video directly within newsfeeds, but will only allow links to Vine videos.

We've reached out to Twitter for comment. So far, no word yet, but we'll update this post if they respond. 

Update: A representative from Twitter told us that the company doesn't comment on third-party reports, but pointed us to a post Topsy wrote to clarify the data points in the Instagram vs. Vine chart. Marketing Land used a free account to obtain data, but Topsy explains that those numbers can vary from Pro (paid) accounts: 

So while the free service gives you a high-level snapshot of the momentum and direction of the social conversation around a topic or domain, Topsy Pro gives you the complete and unfiltered picture that accounts for every single tweet. Because influencers tend to move faster than the general social media population to try the newest things—which is part of what makes them influential—new trends or changes in the direction of trends can appear amplified in charts generated by our free service. 

It’s important to understand how this amplification effect works when using our free product, since there are occasionally topics that get a disproportionately large amount of attention from influencers. This is what’s been happening as the social conversation about Vine and Instagram has evolved.