What is the real difference between these two URLs?
1. If the website has a hover menu at the top, then the subcategory URL pathway will be linked in the homepage. As I understand it, so long as the page is linked on the homepage it doesn't matter how many forward slashes (/) you have on your URL. Is this true?
2. Does it matter if the "category1" page contains only links to the subcategories and little or no writing? Will this affect rankings and if so how?
3. Does it make any difference to Google whether you use an information page to display as your subcategory, rather than using the subcategory itself? (ie. create a subcategory to nest under the main category and give it an SEO keyword, for example, "subcategory1" and then create an information page with the same SEO keyword, so that the website then displays the information page.) Will this affect sitelinks?
4. What is the best way to create sitelinks? Any tips would be greatly appreciated.
1. True in the sense that the depth of the URL is determined by clicks from home page and not by a number of slashes in URL
2. Do you mean affecting ranking of the category page or other pages? It may affect ranking of category page if there is no sufficient content. It may affect the ranking of the whole site if you have many such category pages on the site that have no content other than links. In this case you may want to consider using meta robots noindex (only "noindex", not "nofollow") on category pages.
3. I am not entirely sure what you are asking here. If by "give it an SEO keyword" you mean having this keyword in URL, it is not a problem on having subcategory keyword in URL and the page shows information on this subcategory. In fact this is a pretty usual way to do it.
4. Unless I misunderstood what you are asking, you cannot create sitelinks. Google does it automatically based on various criteria that are not really known. Page usage statistics may be one of criteria and how strong the page is within the site may be another. Good information architecture can emphasise strong (hub) pages.
I would just like to add the following: you do not "create" category and subcategory by purely adding a category and subcategory folder to a URL. Categorisation is created by site structure, not by how URL looks like. Whilst it is a good practice that URL reflects the site structure, this does not work other way around, i.e. having a bunch of pages and allocating URLs to them that present category and subcategory will not result in Google seeing these as category and subcategory without organising pages on your site in that manner.
1. I read somewhere that the URL length may affect ranking - is this nonsense?
2. You understood correctly. In that case, I shall add content too.
3. My website's backend platform offers two options: category pages and information pages. The only difference I can see is that the information pages don't have meta data, you can't nest them under categories (the only way to use them is to give them an SEO and then link to them from a category page) and you cannot assign them with an image. Should I just avoid using these at all? I can just use category pages and fill them with whatever info I want/need.
4. I realise you cannot create them, but any tips will help :)
As an extra question: Do nameservers defaulting (changing to something other than your correct nameserver) cause you to lose your google page rank? I had a 4/10 rank, and it is suddenly 0/10...