If you're writing online, for God's sake use a newline to break a paragraph rather than indent.
The space you save with indents is trivial and the whole point of paragraphs is to keep ideas that are logically separate physically separate as well. Newlines help to reinforce the separation.
It's not like space is such a premium on a computer anyway when most viewing is still on some sort of electronic device.
So do the world a favor and stop using indents.