You're the guy who came up with Enhanced Steam? I can't thank you enough for that, those features are awesome.
Yep, I'm the guy.

Glad you enjoy it and if there is anything you need please let me know.
While ES is certainly fantastic and I can't live without it, it's rather silly to assume Valve is copying features directly from ES. Everything they have added thus far as been logical and requested billions of times, it just so happens that Jshack beat them to the punch. Valve moves slow as hell, we all know this. I doubt this some nefarious plot to steal the hard work of Jshack. Gaben is running out of shit to do and it's time for them to start focusing on the UI and website overhaul that people have been asking for an eternity.
I'm not alleging that they're copying features from Enhanced Steam. In fact, most of these features exist in Enhanced Steam solely because they make sense on a storefront like Steam. Almost every feature I code, by the time I'm done I think to myself "Why doesn't Steam already have...?" Like, "Why doesn't Steam already have an empty cart button?"
This is just the next logical progression of their store, and i totally get that. Part of the reason people are upset about them "stealing" features (and I got quite a few emails about this since yesterday) is that they feel like Enhanced Steam has kind of been used by Valve as a testing ground for new ideas.
Making features that work in all of Steam's language and country configurations is pretty hard work actually. When I ship new features, they're going out to millions of people - some of these features work and some don't. Valve is paying really close attention to the features that work. One user wrote me and said "They're learning from your successes and failures" and I think that's pretty accurate.
The issue crops up because most companies pay for R&D.
I don't necessarily think it is a plot to steal the hard work of jshack, but I do feel as though his work may have motivated them to move a bit quicker. As more and more people use a web browser and ES to browse the Steam store, Valve loses more money and so do devs. The more data consumers have to make informed choices, the lower prices they end up paying. Thus Valve has an incentive to improve their client to provide some of the less damning info, and try to keep the user base within the client for purchasing.
Also this. The more useful features they can provide themselves, the less reason people will have to go looking for something like Enhanced Steam. Since over 1 in 75 Steam users has used Enhanced Steam at some point, they're certainly catching on to stuff like this. Of course, I've sent them numerous emails explaining that I'm not trying to make them lose money and that if they request that a particular feature be removed all they have to do is ask.
Also, it looks like they're adding a fairly prominent DRM warning to store pages, so they're also taking ideas that benefit the average consumer.