bluntforce - 5:52 pm on Aug 24, 2013 (gmt 0)
I have a one page "site" that currently ranks 25 out of 2.5 million results for it's keyphrase. The only links are comments.
I have a three page site, each page is a totally different subject and links out to a relevant page on that subject owned by someone else. My site doesn't rank for any keyphase, but one of the "linked to" pages bumped up around 8 spots for the keyphrase shortly after the link. The other two subjects are probably too competitive. Again, the only links to my site are comment links.
NOTE: Care was taken to make sure pages I was linking to weren't the main focus of those sites and if I noticed any negative effect I'd immediately pull the link.
For those sites, I'm currently measuring how long it takes ranking to degrade knowing that comment links have a limited life effectiveness.