99.9% of the time, No. Only if you change to something with a lot of frames or anything that would prohibit SE's from reading your text. Most WP themes don't do that, so you will be fine. Change themes as many times as you want.
Normally the wordpress theme are well done, but you can find some rubish templates too. It's very important that the wordpress template do not insert meta information, etc, except the ones inserted by default by Wordpress.
Well i am a bit surprised to see so many incorrect answers.. Yes it can definitely affect your ranking in search engines. As a blog theme can determine many onpage SEO factors, which are very important in SEO.
Some themes just suck but if you know your basic SEO, I don't see how a theme designers lack of SEO knowledge can affect what you do to your blog and how you optimize it. Yes, I'd like to hear a little more substance to these answers as well since I have never had loss of ranking, traffic or SERP's because of a theme change.
Yeah if it's not seo'd properly and different than your previous theme then yeah it will effect it. The changes may not take affect right away but will eventually if you don't fix it. Read the theme's details before choosing one make sure it's all seo'd the way you want it. But I agree with hmansfield, I was more talking about some of the older themes or low quality ones. Any of the newer ones are pretty much all seo ready.
A theme can determine usage of H1 and H2 tags. It can also determine the number of images being showed on the homepage and also img alt tags. Apart from this it can also determine which sections get direct links from the homepage and which don't.
Well you would have good SEO optimized themes. The question was can changing your blog theme affect SERP. The answer is yes... If it ignores onpage SEO factors.
The onpage SEO, is not affected of the wordpress theme change. Because a normal Wordpress template cannot be affected by this. There are some rules that a normal Wordpress templates need to follow. Of course you can find many many rubish wordpress templates. Ovi
Still i have few doubts in my mind regarding same Anyway i need to search more in this direction. DON.
Yes it does affect. 2 months back I changed the theme for one of my blogs and bang, the traffic from SEs dropped and so did my rankings. Just recently I recovered from it but now made a permalink migration and BANG back to the starting stage with SE. But I am positive that the site will eventually recover its ranking.
It does affect big time... I wrote my own theme and had to do several tweaks for the best possible SEO. My recent post is about blog content organization for better SEO.
I'm with you. I don't see how a properly coded theme (W3c) compliant makes any difference to SEO. SEO is something that you do. Unless you have coded your tags and descriptions into the header file, instead of using a plug in, and don't update your permalink structure, I don't see it making a difference. All you image tags, on page SEO, incoming links, and everything else should be the same. There is no reason for a theme to change that.