'Influencer' has become an all-encompassing word for bloggers, vloggers, Instagramers and others that have a strong social media following. 'Blogger' tends to refer to those that write a blog – either on their own domain or through a blog hosting website such as Blogspot.
SEO blogger outreach is primarily concerned with growing your backlink profile, while influencer marketing is more about brand awareness and boosting referral traffic. Before you embark on an influencer marketing or blogger outreach campaign you will need to define your goals. If you are looking to elevate your brand awareness, then increasing backlinks will not be your primary target.