Can do it! is a commercial paradigm that can be used in various occasions. For example :
- when you need to entertain voters with false promises telling them that they can do it!.
- when you sell Jordan sports shoes with motto - just do it!
- when you're in marketing team, and doing all that team-building crap - you can (usually) do it...

Can do it! by itself means nothing, and it's pretty much all it is.
Can do it! needs an object, predicate, which is usually by every means so irrational so it can poly-morph to anything giving great results by means of good-emotional overwhelming of masses ..