One thing that has always felt a bit odd about certain digital distribution platforms is when they aren't accessible anywhere other than their originating device. It makes sense that games cannot be played on every device, but why not allow shopping? Sony seems to have finally come around and provided a new and simple means to access the PS Store without having to turn on your PS3 or Vita.
It also seems to be one of the few places that Sony has obviously changed the naming to be "Sony Entertainment Network". Either way, you can visit the page and browse through the store just as you would on a system. At least, it appears faster than the system-based version, but otherwise looks very similar. Perhaps it was even the recent Store update that was required to allow the service to be viewable online. Unfortunately, the pages currently live are for European customers, not US ones, although that version should be live soon.
As you might expect, using the online storefront connects with your account to (if you want it to). This means that you may purchase items on the site while logged on to your PSN account so the titles are added to your collection. So far, it doesn't appear that the system will allow auto downloads of this remotely-purchased content like XBLA, but perhaps that functionality will roll out later.