Hi there.
I'm guessing this topic is quite old now, but I've just come across this problem and so thought I'd address it here. Hope that's OK.
I would like to suggest that indenting paragraphs with a colon is not the way forward, mainly for accessibility reasons.
For those who don't know, I am totally blind and use a screen reader called NVDA. It does various processing on the content it retrieves from different applications including web browsers, documents, emails, interface controls and the like in order to try and read it, either in braille, or in my case using text-to-speech technology.
While visually the result of the colon may be indenting the text, what it's actually doing in the HTML is creating a described list (for those with a knowledge of HTML, the dl and dd tags). So when paragraphs are indented this way, screen readers are processing those tags and recognising a list where in actual fact there is no list.
Example:
I love WikiTree.
Come and join me there.
A screen reader would read this normally.
:I love WikiTree.
Come and join me there.
A screen reader would read the following:
List with one item I love WikiTree.
Out of list Come and join me there.
Now imagine reading all those list announcements for every paragraph in a long narrative.
For that reason, if you're going to indent I would definitely suggest using the &bnsp combination, as literally all that does is add extra spaces, which a screen reader would read normally.
Cheers.