If I allowed guest post in my blog and if those authors want to add credit or link to their website/service in last paragraph. Then it will effect on my pagerank or seo of my website.. Does it related to OBL...OUTBOUND LINKS..?? should I allow that, since I read that more number of OBL, your website rank and reputation will decrease...Hubpages and other site allow user to add one link in their article...
some outbound links are ok. it's not to using them exessively. sometime ago, my PR changed from too many links on the home page. It took a long time to recover. I limit my home page to less than 10% outbound links.
If it is a relative site, and the page is dedicated to that article (i.e. there are not a ton of other authors with outbound links) - then go for it!!!