With a mysterious Facebook product launch coming up on Thursday, the rumormongers think they've landed on yet another possibility for what's to come: a video competitor for Twitter's Vine, made by none other than Instagram itself. You know, even though the rumormongers believed something else entirely just a few hours earlier.

When the social network's old-school paper invitation landed in mailboxes with a coffee stain on Friday, TechCrunch's Josh Constine was "pretty much positive" that it signalled a Google Reader replacement was on the way in his article titled "Facebook Will Launch A News Reader At June 20th Press Event." This morning, however, TechCrunch changed its mind, walking back the RSS claims in an update that says Facebook "may" launch a reader, "Or A New Way To Share Videos." That's because, well, today sources tell TechCrunch's Ingrid Lunden that Instagram, which Facebook owns, is working on a short-video sharing feature not at all unlike Vine. 

While Vinestagram would fit right into the Twitter vs. Instagram narrative that has emerged ever since the filtered-photo sharing app took away its "cards" capability from Twitter, this rumor sounds anything but certain. First of all, the paper invitation, with that ominous stain, has to mean something. An RSS reader fits into those types of "clues" more than a Vine competitor does, as Constine explained in the original TechCrunch "scoop: "The conspicuously analog invite was sent out via paper snail mail instead of by email like Facebook usually does. There’s also a coffee stain on the invite," he wrote. "You know where else you find coffee stains? On the newspaper, while you’re reading it, over coffee." 

To that end, Lunden even doubts the accuracy of her own source. "This could be an intentional blind alley," she writes. But by that logic, so could the invitation, she adds. "But if the Instagram video report is true, you could say the event invite itself — sent by snail mail, coffee cup stain charmingly in one corner — is a red herring of its own." Facebook, of course, remains mum.

In addition, considering the popularity of Vine and considering Facebook's affinity for copying apps, the Vine-like video service makes more sense than a reader, which doesn't really fit into the social network's mobile oeuvre. And that new hashtag feature Facebook just launched might make more sense for video tagging than it does complex news-story organization, which Facebook is already attempting with its new News Feed. Plus, short videos could eventually support some sort of advertising. But a news reader? That doesn't do very well with ads, as Google has learned. But who knows: Maybe Facebook is building that RSS feed of your dreams. We'll have to wait until Thursday afternoon at 1 p.m. Eastern to find out the details.