I actually have the category name in my url like:
http://blog.com/en/category-name/blog-post-title/
But If one day I would change this category name, My url will change for all the blog post in relation with this category, then I will loose all my social shares.
Is it better for me to delete the category-name and just tag my post with the category name ?
I will have:
http://blog.com/en/blog-post-title/
I ask because I care about SEO but I'm not sure if it's better for google and others to have key information in my url.
Thank you in advance
This likely goes without saying - but just in case - anything related to SEO is really opinion - so I'll try and stay to what I have actually seen effect rankings over the last 2 years with Google specifically.
The first part of your question - IF I go back and change the category of some of my blog posts - which then in turn changes my URL - then YES I would say that could hurt your SEO efforts - as previously mentioned Google may see the older pages that had been previoiusly crawled now as a 404 Error - Page not found - and if you get enough of those it could hurt your rankings.
And - in my opinion - you actually want to make sure that you pay MORE attention to optimizing the category name than you do the post name as Google still values [from what I have seen with my own and client sites] those keywords in URLs closer to the root domain than it does keywords found further down the url. So YES I would argue with the more popular Wordpress permalink post stucture: yourdomain.com/category/post-name - that the category slug in the URL is MORE important than the post name.
Example #1: www.YourDomain.com/running/how-to-lose-weight Example #2 www.YourDomain.com/how-to-lose-weight/running
All things exactly the same with the content on the actual post - I would go with Example #1 if I was targeting the keyword "running" and #2 if I was targeting the keywords "how to lose weight".
IF you intend on changing something later down the road - then I would suggest that you plan on producing additional content and post new posts or pages - Google is placing a high degree of importance on NEW - ORIGINAL content producted on a regular basis - so in the Running/How to Lose Weight example above those could easily be two different unique posts - with unique content - just switching the post name and category name.
So much can go into the URL sturcture of a Wordpress post or page - and I feel like it is typically over looked - or maybe more accurately stated - not looked at enough.
A great place to see how Google views your keyword density [including urls] is Webmaster tools - look at Google Index -> Content Keywords.
Great example of keyword density getting all sideways - is with physician practices - they want to say target Plastic Surgery - yet the main content keyword on almost all physician sites is "Patient" just because naturally that shows up a LOT on physician practice sites.
Hope that helps some.