Against them are Nofollow links. They can be normally not accompanied by search engine crawlers, they don’t normally pass on link fairness from just one website to another, plus they’re ideal for paid out or sponsored articles at the same time for person-produced material (UGC). Upwork isn't a specific marketplace https://socialwhoop.com/product/we-will-provide-backlink-and-guest-posting-article-on-our-da50-pa33-website-blog/