To index or not to index -- Blog Comments

I have a decently ranking blog in the expat niche. I post new content around four times a week.

I have a fair amount of comments.

I have comment indexing turned off. I once read an article advising that and it gave good reasons but after a year and a half I don't remember what it said and I've learned a lot more since then.

Seems like I could dilute the power of my own articles if I turn it back on. Leaving it off, I'm reducing content. Sometimes though, what people say is best not on Google.

So what are your thoughts?

On a side note, I have a buddypress site that is in the same niche, its only a few months old and I'm lucky to blog once a week. On that site, I have comment indexing on. Seems to make sense there.

Hmmm, I have a plug in called nofollow free installed. It makes the author link follow. Am I destroying the benefit I'm giving them if I don't allow it to be indexed? I don't think my SEO plugin gives me the option of noindex follow.... perhaps I will look at the source.