Meh, the problem and it's solution isn't that original so I wouldn't scream ripoff just yet. Also The other site want's you to install an extension. In my personal experience (a while back so don't know current situation) it was a bit buggy, and the offline reading thing didn't work very well. With this you can have sort of the same (minus offline reading). I still prefer delicious (tag: toread or towatch) though, have to admit I'm a bit of a fan of the delicious site, so I'm not that objective.

Edit: How do you plan to monetize this service? Or is this more for fun?