How Content Changes Can Affect SERP Rank?

Sure you can lose SERP rank by messing with page titles. A page title is one of the strongest on-page ranking factors for Google SERPs.

If it's something like a Wordpress CMS & you mess with both the page title & URL, your literally starting over on the SERPs because static URLs are the single most important thing for SEO. Once a page is ranked, never mess with the URL for that page.

changing post content and title WILL affect your post and is not adviceable,
why not add new post? the old post still gets traffic, why trow that away
creating a new post is the way to go here, more posts, more content, more traffic.

you can always use old posts to redirect people to your new post by using a link on the top of the post or something like that, many things you can do with an old post you think you dont want or need anymore, but leaving the content and title untouched is always the best way to go if you ask me.

i have hundreds of old post laying around the internet that still get some traffic, sometimes i just paste a link in the top of something new i am promoting and i syphon all that traffic towards my new content, free traffic for nothing!

good luck!

Instead create more posts but don't touch the old posts that are already ranking...

Traffic could go up or it could go down.

When I'm doing what you are about to do I look at current rankings/traffic and try to add more emphasis on what's ranking and modify what's not ranking.

So if I have a webpage ranking for "This Reasonable Traffic SERP" I'll try to add more relevance to the SERPs giving traffic, that can be better optimized content, more links using the SERP and derivatives as anchor text.

For webpages that aren't generating traffic might step up the backlinks or change the main phrases targeted. Depends on a lot of factors, if I find a SERP just isn't happening I might drop targeting it and go for something easier.

Just started reanalyzing my Stallion Theme site (link in sig), when I wrote most of the content I targeted some hard SERPs and struggling to compete (SEO SERPs are highly competitive) as I've not been building links, so going to rewrite the content to target longer tail SERPs which require less backlinks. A year from now if I get around to building new links I might rewite again to target harder SERPs. The whole point of SEO is to generate traffic, so you target SERPs you can get for a reasonable investment in time etc...

David

Thanks all
@yukon
I'm talking about changing title not url (with higher traffic Kw)
@pietjeplukt
Sometimes it going to be confusing to add posts within two keywords have the same meaning, in order that I'm trying to find a way to edit the old titles and update already published content (only add content at the end of the post not changing the entire old content)
@SEO-Dave
Actually I did added content to old posts and they skyrocket traffic>> but that was 2009 -2010
I am not sure now what is going on?!!
So that I'll keep it as you all recommended.