As an SEO that works primarily on Magento websites, one of my biggest frustrations when doing audits or consultancy work is SIDs / sessions IDs! Session IDs are most commonly caused when a link is from one domain (or most commonly a sub-domain) to another – and the SID is appended to track the user’s session.
Session IDs cause a lot of duplicate content issues (because they’re creating lots of duplicate variations of your existing pages) and they can have a massive impact on crawlability. The best way to get rid of session IDs is to simply eliminate the links from the sub-domain (usually a https page, caused by the SSL certificate being on the non-www section of the website) and adapt the site to prevent the issue.
There is an option in the back-end to not use SIDs (configuration > web), but it doesn’t work. If you have a strong development team – this article will help you to prevent SIDs from being served.
If you’re in a position where this isn’t possible or you don’t have any Magento development resource, you’re going to need to utilise meta robots tags. This isn’t an easy thing to do manually, but it can be done quickly and easily within our plugin. All you need to do, once you’ve purchased and installed the plugin, is assign a REGEX match rule in the back-end. The regular expression would simply look like this, “SID.*”.
Feel free to drop me an email if you have any questions about this. You can also read my full guide to Magento here.