Anytime you have a question about site policy, L'd think your best bet is prolly gonna be submittin' a help ticket, via either the "Help" or the "Contact Us" links in the footer of every page. I think thats pretty much what they're there for - gettin' help :wink:
But to give ya the short version here, off the toppa my head, I'd hafta say the key word is "Promotion" - in general, a website with which you have no affilliation, and which itself is neither promotional or otherwise objectionable (solicitin' funds or membership, or somethin' like porn, hate, or other illegal content or intent, for example, is prolly OK for a link. In fact, if quotin' from an article, news item, or essay on another website, its good form to provide a link to the source. Another "In General" rule-of-tbumb is that linkin' to a webpage containin' an image or other graphics file of acceptable nature (again, not porn, hate, or otherwise illegal) may or may not be OK, dependin' on the webpage itself, but linkin' directly to the image itself is prolly OK as long as the image itself is OK, and would be the preferred method. "Check out this neat website I just found", "Go to my website/blog", "Sign up (here) for (whatever)" - that sorta stuff - is just about always a no-no, it seems to me.
Hope I didn't confuse ya even more ... thats always possible when I think I'm explainin' somethin'
... I just figure a help ticket might be the way to go for a question of this sort