They've been displaying pdfs as text for some time but it was very ugly — just enough to quickly see what's inside. “Quick preview” is new feature. They render pdfs but have raw text too for convenient copy/paste.

Google's reader should be much more light and perform faster, esp. in old browsers with slow DOM implementation. The disadvantage of this solution is non-native (for client) text rendering. Also things like embedded video and scripting would not work, but I think Scribd is not supporting those either.

So, not at all the same thing. Whoever downvoted you have some explaining to do.