This is certainly true, especially when you're only trying to create a feature of an existing product. There are however, recent examples of features from other

This is certainly true, especially when you're only trying to create a feature of an existing product. There are however, recent examples of features from other products turned into successful services on their own (FriendFeed is one example that comes to mind). The flip side is that there is very little new under the sun, even in technology, so successful products are more often than not the result of innovation as opposed to invention. I know Paul Graham has written about this, and it has certainly worked for companies like Google. One important feature of new tech products is the whole product concept from Crossing the Chasm. In our field, where things are changing on almost a daily basis, it's hard to determine what the whole product may be but companies with this mindset and approach are much more likely to succeed than others.