Let’s say you ask or answer a question and you want to include a great website as a reference. How can you make sure your link doesn’t violate the Answers Community Guidelines? Here is a refresher on what is acceptable and what may be an infraction of the Community Guidelines. What’s considered spam? Spam is unsolicited email. A spam answer usually has little or no relevance to the question, containing either a link to a spam page or an email address. If you notice someone repeatedly answering questions with a link to an unrelated site (usually a site offering money or selling products), report it! You’ve found a spammer. What about links in an answer to a question I posted? Some people end their answers with “Please answer my question: http://answers.yahoo.com/…†But the question they link to often has nothing to do with the question you were asking. This kind of linking violates the Community Guidelines - it is the same as spamming unsolicited links. What kind of link is acceptable? If you know a website or a book that might help the asker, by all means include it in your answer! Just paste it into the “Sources†box on the answer page. You’ll help make your answer more thorough and useful. By posting relevant links in the “Sources†box and by reporting spam, you’re helping to make Answers a better site via http://yanswersblog.com/index.php/archives/2009/06/03/about-those-links/
When I answer there, I make sure my sources link is relevant to the question asked. When you do that I don't think there will be a problem at all.
Dont make it obviuos that you're trying to promote a particular website through your answer. That'll lead to suspicion and someone might flag it off as spam...
If I put a link in my answer (I don't always add a link) I make sure it deals with the question. I am not afraid to link to other sources too. Hopefully it adds to the creditability of my answers.