And yes, it would be rather odd for a website to have only one internal followed link.  It is possible that something funky with their CMS has all links no-followed, but even then.

Hi Becky,

So first it is important to note that the Moz Link Index (MozScape I think it's called?) is not a complete picture of all the links on the internet.  So if you see a website ranking better than yours, but you have better links according to Moz, try checking a tool like Ahrefs.com as a "second opinion" on what links each site has.  Sometimes the best ranked sites only have a handful of links, but they're incredibly focused links from valued sites in that industry.

A great example of that is Moz itself, none of my local competitors have written content for Moz over the years, so even if they have some really good links, or even more links, the few links I have earned by having YouMoz content promoted to the main blog (and just the YouMoz content itself) have given me some very specific valuable links from Moz, arguably the most authoritative website on SEO that exists.  So that one link is just worth a ton in Google's eyes, vs. my competitors who haven't earned that link themselves (even though they could, probably easily, but don't tell them that).

When you're asking about internal links vs. total URL links, unless it specifically says "internal" links or "external" links it probably means all links.  Internal links (just covering all the bases) are links inside your website to other pages inside your website, ie a link from your "homepage" to your "about us" page.  That is a sitewide link internal to your website that is probably in the menu of every page.  Only links that are internal would be counted that way, and it's a safe bet that the Moz tool has found 100% of the internal links on your site.

Now external links - again the Moz tool may or may not have found all the links on the entire internet that point to your site and your competitors sites - but those are links from when another website links to your website, from one domain to your domain.  So when we're evaluating value in a link report, we're saying "Okay this guy has 50,000 links and I have 12 it's probably going to be impossible to compete with him for these primary keywords".

Alternatively, you may say "I have 500 links and this guy has 3 and he's kicking my ass, what gives?!"  That comes back to the fact that not all links are created equal, again similar to how my competitors might have more links than me, but I just have better links.  I've done guest posts, I've been interviewed about SEO, we monitor HARO religiously for anything SEO or marketing related, etc.  Our links are few (because we rarely focus on our own stuff) but they're of such a high quality that they make up for the lack of volume (in many cases).

Now saying all this - and forgive me if I said anything you already knew, I just wanted to be sure I covered the basics before moving on just in case - your question is ultimately "Can I trust the SERP Report as a means to show me how my stats rate vs. the sites I am trying to beat on Google?"

I'll go un-vague and just say... No.  You can't.  You shouldn't rely heavily on that tool as a means of generating a "To-Do" list for your website in order to help you rank.  Link metrics are incredibly important, arguably worth more than anything you can do to your actual website (outside of creating outstanding shareable content) but at the same time not all links are created equally, so if you are using the SERP tool and saying "I have better numbers than person in Rank #1, I should be doing better than them" you are going to wind up pulling your hair out.

There are hundreds and hundreds of factors that go into Google's algorithm, maybe less broad there are dozens of factors that we generally look at from a "low hanging fruit" perspective on what we should change to improve our rankings.

I always run the on-page Grader tool from Moz when I am comparing pages, to see if there are any obvious keyword problems or if the Title tag is lacking in focus.  The Title tag is incredibly important.  One of the biggest resources that Moz creates is their Search Ranking Factors report, so if you wanted to review your website vs. that report, you might find some items where you know you are lacking and then that gives you an idea of what should be on your ToDo list.

The SERP Report isn't going to be a good gauge of like... if I go from 50 to 150 links I will beat competitor X, because that assumption is based on all links being equal, which they are not.  Google cares about the age of links, the authority of the linking site, the relevance of the content, the social shares of the content, etc, etc.  Everything has a footprint online so the bigger the footprint the more noise it looks like it's making the better it is assumed to be.

This is probably way more of an answer than you wanted, but there you go.  I recommend you dive into the Search Ranking Factors report from 2015 and see if anything there pops up as severely lacking on your site, and see if you can target those items to make a big difference.  Just keep in mind, even that report is based on the opinions of hundreds of SEOs so while it is really good, it is not a guarantee'd roadmap for ranking well - there are few guarantees in search.

Moz's 2015 Search Ranking Report - https://moz.com/search-ranking-factors

Hope this helped!