I didn't make up that title, Microsoft did. To coincide with the launch of the New Xbox Experience, Microsoft has launched a browser based version of the Xbox Live Marketplace.
Currently you can't make any purchases as it seems they're not quite ready yet. But rest assured, it should be up and running within the next day or so.
When this finally gets working, it should be quite successful. For one, unlike the Playstation Store for PC, you can purchase anything that's available from the 360 marketplace. So if you can't get to your 360 but you just have to have that Grand Theft Auto DLC ready for you while you're at work, you can. And to me that's just cool.
To compare, the Playstation Store for PC now requires you to have A) Media Manager, a PC app; no Mac support and B) a PSP. Prior to this highly flawed system, it was viewable right in the web browser but only offered limited PSP content. If Sony, or Nintendo for that matter, adopted a system like Microsoft just has I'd be very pleased.
UPDATE: The Marketplace is now completely live!