The intention is not to stop creating new software. If the OP's basic idea
of the new software is completely novel then creating a new software is
worth it. But if one says "I'm going to create a software exactly like
facebook", then what is the use when an equivalent Free Software exists? If
the OP's new software is intended to have extended features, then adding
those features to the existing software makes it more usable.
"Creating" is half the fun of knowing to hack and especially if
it's a hobby/passion.
Studying the existing software and modifying it is more of hacking than
what
creating is. A good programmer should be able to study and analyze others
programs as well.
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