It’s a bit early to be thinking about SEO, but as time progresses it will become more of a concern, especially for a site facing the World Wide Web. As it turns out,
target has practically no SEO value unless it affects the quality of the site. It is a bad idea to use the attribute if the URL is to a local site resource. It kills the Back button so the user has no history to fall back on when attempting to return to the page that sent them there. For this reason, it should be reserved only for links to other sites.
Bottom line, use this attribute with great care and deliberation. Do not treat it trivially.