Ryan Singer at Signal vs. Noise – Features are a one-way street:
"Whether the feature is good or bad, once you launch it you’ve married it. This changes the economics of feature additions. If you can’t destroy what you build, each addition holds the threat of clutter. Empty pixels and free space where a new feature could be added are the most valuable real estate on your app. Don’t be quick to sell it, because you can never get it back."