Good work, we need Phishing Link Checker for steemit!
Can you add a logic that gives a warning when going to a similar URL. For example. steemlt.com (i is replaced by a l). There are also fishing attempts with UTF-8 urls, which look very similar to the original URL, but have a small dot below the m.
How about making a steemit post with a special tag for adding new URLS. You browser extension could then read the post content and could create a list.