I blogged on weird ebay a couple of minutes ago, about a tin of Baked Beans that I'd found whilst browsing the weirdness. Got me thinking, and searching for more weirdness. I discovered that it is quite possible to buy your groceries on ebay! 
Now, I love ebay and I shop at a large supermarket chain for reasons of convenience (ie, I'm too lazy to walk further than round the corner for my shopping), so perhaps I shouldn't really be commenting on what's in my mind and needs to be written down. But I'm going to anyway! 
Ebay today, and something last week, got me thinking about how it could be possible, one day, that we buy everything from one large shop (Tesco, Sainsburys, et al).
In my town, Sainsburys have had a presence for at least twenty years. And it is an imposing presence. When they first opened in the town, they put many smaller shops out of business. They've also expanded the store every so often, and now they are redeveloping and expanding again - taking over the neighbouring pharmacy in the process.
Here I ask, where will this all end? Will Sainsburys continue expanding, and take over the whole street? What happens to this choice that free markets are supposed to bring, when all we see is one large supermarket taking over and dominating. Are we destined for a world where large companies control everything, and we have no choice to go elsewhere?
Sounds so much like Sci-Fi coming true.
Abilene
Near where I studied for the last three years, there's a large Tesco store which not only sells food, but clothes, CDs, stationery...getting close to everything under the sun! Scary, really! 
In the States there is a jokey (yet scarily true ) expression.
"If ya can't buy it at Walmart then ya just don't need it"
Basically it means that the Super-Walmarts in the States sell everything from milk to horsefeed to oil changes. I kid you not. Not bad for old Sam who started out with a bitty store eh? * rolls eyes *
Isn't Asda owned by Walmart?