St Kilda when that remoter outpost was evacuated in the 1930s but it's only 60km from the nearest Tesco in Lerwick [20km by ferry to Walls, 40km by winding and windy road to the metropolis]. Social services and infrastructure have moved on since then and I don't hear any rumours that Foulanders are going to give up anytime soon. They used to be fisherfolk almost exclusively, but now are more crofters and there are far more sheep and ponies about than people. Contributing at least as much income is the servicing (B&B, guides, deer-stalker hat sales, binocular-hire, clothes-driers) of twitchers because the island is rather rich in bird-life which is hard to come by nearer the centres of population further South. The island has been designated a Special Protection Area (SPA) for birds, as well as a National Scenic Area and a Site of Special Scientific Interest (SSSI).
Among the highlights are more puffins Fratercula arctica than you can shake a stick at and the world's largest colony of Stercorarius skua, the Great Skua or bonxie. Stercorarius parasiticus the Arctic Skua is also common hereabouts. Apparently the Anglophone word skua comes from Faroese skúvur, one of the very few English borrowings from that direction. Faroese is spoken further North by 65,000 people mostly in the Faeroes but 20,000 making a living in Denmark and elsewhere. That's almost as many people who speak Irish in Ireland. Faroese is descendant from Old Norse which was spoken by Vikings and written in runes when those people burst from the poor-scrabble farms and fjords in Scandinavia and sought a an easier life elsewhere. Old Norse evolved into Faroese but also Icelandic and Norn which last was spoken in the Norse fiefdoms of Orkney and Shetland for at least 500 years. The language started its slow decline just North of Scotland when Scots-speaking lairds were granted holdings and serfs on the islands and eventually these magnates stopped swearing allegiance to Denmark and started sending their dues South to Edinburgh. As Scots, which I think is a language distinct from English, came to be spoken in Castle and Manse as the language of prestige, so Norn was spoken by fewer and humbler people. The same process swept Gaelic out of mainland Scotland in more or less the same time-frame. By the time scholars perked up to the existence of another language spoken by natives of the United Kingdom, Norn was gorn. The last attested speaker claimed to by Walter Sutherland of Unst, and he died in 1850. It must not be confused with the somewhat jocular Norn Iron which is a phonetic pastiche of the language/accent spoken in Belfast.
Interestingly, to Norwegians Shetlanders sound like they are speaking Norwegian by their timbre and intonation until you get up close and find they are yakking in Scots with a Norse accent. It's a bit like Richard Feynman being confused into thinking that two chaps on a plane conversing in Ladino were speaking Portuguese. The other peculiarity of Foula is that they are still working on the Julian Calendar with Christmas celebrated when the rest of us have moved on to Epiphany / Twelfth Night / Nollaig na mBan. Whatever!: I don't think that makes much difference to anyone else.
I think I feel a Summer holiday coming on: rock-art, puffins, beach-combing Foula should be good for a tuthree days.