I'm not implying that profile links can not be effective for ranking or that everyone using profile backlinks is shady.
One person isn't to be able to be expert in all aspects of search result optimization. Some SEO experts have lists of sites that accept automated link exchanges. https://click.accoona.com/k.php?ai=17903&url=http://bioinformatics.org/seqlink/top_off-page_optimization_-_the_7_ideal_way_to_get_t_affic