hello 1)First question if i choose subdomain i use as name for example wordpress.example.com is any problem with wordpress or any one ...or .. google..... 2)second: my website hit it by panda; and i decide create subdomain as i said before, is this subdomain to be infected by low ranting for domain from google in future or google consider each one is separate;
I don't really understand what you're asking with your first question. Can you clarify? In regards to the second question, a site doesn't get "infected" by Panda. Panda simply devalues pages for which it considers the content to be low quality or spammy and sites which it considers to have too many ads, especially at the top of the page. If you correct the aspects of your site which Panda would not like, then you'll not have a Panda problem anymore. In other words, you should create good, quality content and make sure your site doesn't have too many ads, especially at the top of the pages. I'd recommend fixing the main site instead of creating a subdomain or just delete the old site and create the site you were going to setup on the subdomain on the domain itself. If you are committed to the subdomain idea and don't want to deal with creating quality content for the main site or redesigning the ad structure (whatever is necessary), then you may want to consider just deleting the pages. Google can and usually does associate pages of a subdomain with the main site. So, if your main site is still a poor quality, ad-covered site, you're probably going to have a problem with the subdomain as well. Also, if you create poor quality content for the subdomain, you're going to have the same problem as you had with the main domain.
thank you for useful reply; for the first question; i mean can i choose subdomain name (wordpress) wordpress.example.com any problem with that or not
Absolutely yes! Once Google loses trust on a website because of its shady practices, it will start devaluing all the pages & subdomains on that domain because it doesn't deserve credits anymore according to them and rightly so.
Jamal, I suppose you could use "wordpress.example.com". I've never heard of that being a problem. Then again, I've never heard of anyone doing it either. Are you specifically wondering if you'll run into a copyright infringement issue?
@lesterj I was going through your comments and appreciate your knowledge. I've wordpress installed on my main website and intent to install a forum. Considering the fact that there would be low quality and duplicate content on the forum, what would you advise - Should I install the forum on a sub-domain or an entirely new domain?
Unless the subdomain and main domain are heavily interlinked, search engines usually treat the subdomain as a separate website, i.e. your subdomain won't directly be effected by Panda if your main domain is.