This is simple copyright infringement, which is distinct from plagiarism.
However, I have another complaint. Why a plain text file? I don't want to have to download some bloated reader just to read this thing. Can someone print to pdf and upload it to something sensible like scribd?
Plagiarism is when you try to pass off someone else's work as your own.
I think what you really mean is "Why isn't this copyright violation?" The answer to that is that I did not in fact "take their entire post and post it in full." (Did you even compare the articles?) I cut out everything rediff wrote, leaving only Larry Page's quotes. Arguably they could claim they have a copyright on the selection and ordering of the quotes, but that is a pretty weak claim.
While rediff may not have a claim on the copyright, they did go through the effort of compiling the quotes. At the very least, link back as a sign of respect for someone else's hard work.
I'm assuming PG did this for his own benefit, and then made it public. Having said that, this is a nitpicky and yet very serious charge - PG, you need to stick in a credit to the original source.
Plagiarism would be taking credit for having written the article. But you're right that there is a potential copyright violation -- unless the copyright owner has given pg permission to reprint the article in its entirety without attribution.
though pg should have posted source link with his note, i dont think that even rediff.com is the copyright owner - to what i understand pg did it in the good faith to help HN readers and that's what it matters ...
However, I have another complaint. Why a plain text file? I don't want to have to download some bloated reader just to read this thing. Can someone print to pdf and upload it to something sensible like scribd?