Magento’s rewrite engine is known for causing SEO issues, with the numbers being appended to URLs being the most common one. The URLs are created when Magento thinks that the URL is already in use or has been used in the past – uploading via CSV can cause this issue because you’re essentially over-writing the existing URLs.
There’s also an error in a recent Magento Enterprise release that causes a lot of these issues.
When you come up against this issue, you need to work with your developer to clean up the rewrites in place, so basically removing anything unnecessary and replacing lots of individual redirects with more efficient rewrite rules.
Layered / faceted navigation is probably the most common Magento SEO issue and it’s also probably the most detrimental.
I would recommend instead using the noindex, follow meta robots tag, which tells search engines not to index the pages, but to still follow the links. You should still have the canonical tag, however I’ve seen very few cases where it’s prevented over-indexation issues when it’s not been added from the start. I’ve also seen plenty of cases where the canonical tag has been implemented from day one of an ecommerce launch, however the pages have still been indexed and lead to duplicate content issues.
In the event that you’re having issues with crawl budget, I would recommend using the robots.txt to block the pages.
Whenever I’ve introduced a blog on a Magento website, I’ve used the fishpig extension, which is basically a WordPress integration module for Magento. The Fishpig module makes integrating the two platforms very simple.
I’ve not seen any benefits of Magento Enterprise over Community from an SEO perspective. The only thing that could arguably be considered is that EE has caching out of the box, so might be faster – but this can be achieved with CE too and is unlikely to make any difference.
The trailing slash canonical issue is one of the most talked about technical SEO issues with the Magento platform, as most URLs on Magento sites render with or without a trailing slash – meaning there are two versions of each page. This generally becomes a problem when large sites have links pointing to both versions, which can lead to both pages ranking and also means the link value is split between two pages.
The obvious choice with the trailing slash issue is to apply a rewrite rule, however whenever I’ve tried this I’ve always had an issue somewhere (checkout, admin etc). I use MageSEO to assign a primary URL suffix (either / or no /), which then ensures that the canonical tag points to that suffix on all pages across the website.