i think blogs is about providing informative content. If you provide informative and user friendly content it will automatically be unique. Everything written by a user is no necessary to be unique. All the content can be found on some or the other website. So i think going with information is much better than concentrating on uniqueness. Nevertheless you can take the ideas from internet and then frame them accordingly and generate a unique content
The content of your blog should be unique and quality. But some time the content uniqueness reliable above 75%. This is not harm you blog posting or not penalize your blog in the search engines algorithm. Thanks,
Uniqueness is the key for the success in social media marketing Without unique content there would be no crawling done by any search engine and there would be no ranking of the site on the web
It depends on the topic of the article and the purpose of the blog, 'cause if you're collecting interesting stuff from other blogs - there's no need to write smth superoriginal, but if you have a topical blog and want much traffic to be attracted to it, then you'll have to take part in the real challenge. in this case your texts should be round 80% unique.
IMHO, Uniqueness is must. Uniqueness of your keywords, Uniqueness of your content, Uniqueness of your page, would be very help you much in SEO ranking.