Original story is as follows: Bethesda Game Studios' official Twitter dropped a major tease this morning, tweeting out the traditional "Please Stand By" message from the Fallout series just two weeks away from E3 2018. Bethesda has employed this kind of viral marketing for Fallout before, and in the past it has led to the announcement of a new entry into the long-running and beloved post-apocalyptic multimedia franchise.
The most recent mainline Fallout title, Fallout 4, was a smashing success by nearly any metric. The fourth (fifth, if you consider New Vegas a "main" Fallout game) instalment in the series saw players explore the wasteland of Boston and the surrounding Massachusetts region. Fallout 4 received extremely favorable review scores and played host to some of Bethesda's finest DLC additions as well.
It's too soon to speculate that this Twitter teaser means we're getting a Fallout 5, but that's one distinct possibility. Another is that gamers will be treated to the rumored Fallout 3 Anniversary remaster, as images of a potential E3 presentation announcing that title circulated the internet earlier this year. Although those images were dismissed as false, it's definitely still a possibility - as is the chance that we'll also get a Fallout: New Vegas sequel or remaster. New Vegas is a fan-favorite in the Fallout universe, and it wouldn't be surprising to see Bethesda bringing that game back to life on current generation consoles.
Of course, one such current generation device is the Switch, something Bethesda has already showed a fondness for with the company's port of Skyrim enjoying immense success on the Nintendo portable console. The many re-releases of Skyrim have likely shown Bethesda that porting a game repeatedly is a perfectly fine business model as long as its a popular title, and something like Fallout: New Vegas or even Fallout 4 would meet the same sort of critical and commercial reception. It's an appealing option that doesn't require the development of an entirely new game.
Whatever the announcement is, however, we'll be getting it soon. Bethesda may like to give fans teasers to lose sleep over, but the company generally makes good on delivering the news in short order. Fallout 4 was announced in June of 2015 and then released in October of that same year, so there's also precedent for this Fallout announcement being about a previously unknown game that we'll be getting as soon as late 2018.