The common thought is search engines consider the sub domain as an entirely different website, but your sub domain may be your competition.  If you are selling yellow widgets on example.com and you are selling widgets on affiliate.widgets.com, you are competing against yourself.

Many of the errors and warning you are getting may be affecting just the affiliate.example.com.

If you site at affiliate.mysite.com, search engines probably recognize the content in the iframe as belonging to the Affiliate Company's website.

I believe you can do the diagnostics here for separate sub domains.  That may help your focus on your controllable content.

There is no link from that page to the 'tag' page - I checked.

If you deleted the tags, then you have probably fixed the issue.  Check when Webmaster Tools last crawled your site.  It was probably before you removed the tags, so the problem should be gone after the next crawl.

Do submit a sitemap in Google Webmaster Tools, it helps with the crawl.  There are free sitemap generators on the web.  I don't recommend using a WordPress Plugin for generating a sitemap because I like to use as few plugins as possible.

But with WordPress you need to use one of the plugins to rewrite titles and avoid duplicate content issues.

If you didn't alter the template files, then that is probably not an issue

OK, I learned something today.

I looked closely.  Linked in is using a temporary redirect, that apparently results in the same as a nofollow.

I keep a little text file with the easiest generic code for buttons to social links, that I can paste quite reqularly.

Many of them are javascript and ugly, but I refuse to link to add this, etc..

Fix them fast.  Look for commonalities in the errors.

Relative Links in Template Files Cause 404 Errors

You may notice a bad link in the header.php file.  If you fix that link, you will fix a bad link on every page.  If the link in the header is relative (e.g. href="/contact-us/") there will be broken links on pages on categories and tags, and more.  For example a the page http://www.example.com/category/goats/page-2/  is going to have a link to http://www.example.com/category/goats/page-2/contact-us/ because of the relative link in the header.php file.

In a template page, links should use the full domain, like below:

[Contact Us](<?php echo esc_url( home_url( '/' ) ); ?>/contact-us/)

Relative Links in Content Causes 404 Errors

Relative links between pages on your old site may have broken when you moved your content into word press.  If you have a link to your contact form in the text of your web pages, it will be broken.  Although you may need to do these individually, it is quick to locate.

Extra Pages?

Extra pages is puzzling. How did you merge the blogs?

A big bonus is YouTube will serve non-flash versions when embedded on an HTML 5 page, so the embedded video will show on page on an iPad.

Some are; some are not.

.edu is not necessarily better than some .com.  If the link is from a university's law school resources pages and links to your site on law books, this may be more valuable, than a student's page with a lot of links to and discussions about what beer is best for getting drunk the quickest.

The Google algorithm does consider the trust factor on domain names.  Because just anyone of the street can't get on GoDaddy and buy example.edu, it will automatically get a trust boost.

Some discussion of the different values of the .edu can be found at:  http://searchengineland.com/explaining-edu-link-value-with-examples-64012

That really depends on why the one site is ranking higher.  Is it's content better?  Google doesn't really care about how nice the site looks, but real  people do.

If you are just now launching a website for your company/organization, it is probably advisable to have only one or you will be competing against yourself - your competitors will reap the rewards.  Keep the domain that is performing better.

Do some searching about 301 redirects when you move to one site.

I would make a very small mobile site (even if it is a single page) because there is thought that Google is liking mobile sites - particularly of local searches.

Some are; some are not.

.edu is not necessarily better than some .com.  If the link is from a university's law school resources pages and links to your site on law books, this may be more valuable, than a student's page with a lot of links to and discussions about what beer is best for getting drunk the quickest.

The Google algorithm does consider the trust factor on domain names.  Because just anyone of the street can't get on GoDaddy and buy example.edu, it will automatically get a trust boost.

Some discussion of the different values of the .edu can be found at:  http://searchengineland.com/explaining-edu-link-value-with-examples-64012

Yes, most definitely.  I just did the exact thing.  I moved a site that had originally been on asp classic, then moved to php, now to word press.  The .asp pages were being processed as php by the server, and there were hundreds of pages.  Within two weeks of moving site to WordPress and doing the redirects I saw immediate ranking results.  Here are just a few redirects, the way I was making them:

redirect 301 /about-fort-worth-personal-injury-lawyer.php /about-for . . .
redirect 301 /arlington-personal-injury-lawyer-locations.php /arlingto . . .
redirect 301 /injury-law-news.php /injury-law-news/
redirect 301 /asbestos-claim.asp /asbestos-claim/
redirect 301 /auto-accident.asp /auto-accident/
redirect 301 /burns.asp /burns/
.
.
.

Here are the steps I took to save time.

• I created an xml sitemap at one of those free online sitemap creators and downloaded as CSV.
• Used the list in php script I wrote to scrape the text from each page on the old site and insert into the WordPress database using the file name as title (replacing - with space) and droping .asp or .php
• I recreated the redirects in Exel by combining a column of the old filenames and the newly created ones. Cut and pasted.
• The new url's were in Google in about 10 days.

The issue is www.EXAMPLE.com and EXAMPLE.com are considered two different websites, and Google may split the links in if people are linking to both versions.  A 301 redirect tells Google to assume all links are pointed at one version.

Your Question: I can see that it doesn't matter whether you type in 'www' or not in the url for a wordpress site, what is going on in the back end that allows this?

My Answer: This is not WordPress, it is your web host.  Most LAMP webhosts will automatically server your website with our without "WWW".  WordPress will create the links on the pages it creates to the one specified in your settings, but the site will come up weather or not you use "WWW."

To Address the Concern: Because you are using WordPress, you are probably on Apache, so add this to your .htaccess file in the root directory.

After:

END WordPress

Add:

Rewrite all old filenames RewriteEngine on

Options +FollowSymlinks
rewritecond %{http_host} ^EXAMPLE.com [nc] rewriterule ^(.*)$ http://www.EXAMPLE.com/$1 [r=301,nc]

Test with and without "WWW." Test with a different browser.

A big bonus is YouTube will serve non-flash versions when embedded on an HTML 5 page, so the embedded video will show on page on an iPad.

OK, I learned something today.

I looked closely.  Linked in is using a temporary redirect, that apparently results in the same as a nofollow.

I like the guest blogging idea for two reasons.  One, it builds links, and two, it allows me to add content to a lot of blogs that are really interested in growing a lot of good content.  But I often read articles that give credit to another article, that give credit to another article.

I have been offered plenty of documents for client blogs, but I am worried that at some point in the future Google will decide all this guest blogging is similar to link trading and selling.

What does everyone else think of guest blogging?

My experience is a dedicated IP is not a great boost, nor worth the money if SEO is the only reason to pay for it - if you are only working with one domain.  If you have 500 domains all on the same IP, and they all have a link to your site, that will probably get a Google penalty.

I am more of a web developer than an SEO expert, and I resell hosting.  Hundreds of accounts spread around about 10 ip addresses on only three servers.  Most have links to my web design site, and it seems to avoid being penalized.

Yes, purchase your name for the 10 years max.  Age of domain seems to help one of my clients a lot.  The ideas is a search engine will have a greater 'trust' in a domain that is going to be around for a while than one that may only be here for a year.

301 redirect is a permanent redirection.  If you set up a 301 redirect and a search engine requests the page, the search engine is sent a reply that says the page has permanently moved to a different location.  So Google will consider the new page as the one to be indexed.  Google will also transfer the value of any links to hp.domain.com to www.domain.com/hp.

In most situations, I believe it is best to optimize one domain than several.  Search engines will consider a subdomain as a complete separate domain.  And yes www.domain.com are considered two different domain names (although I suspect Google tries to sort that one out). Using the 301 redirects to the folder transfers the value of the links of the sub domain to the file in the folder, which is also a link in to a place on the domain www.domain.com.

Search how to do redirects, there are many tutorials for different platforms.  It is not difficult.  However if you are using one of those free hosting sites, you are not going to have any luck.

Search the Joomla Extensions directory and choose one of the canonicalization extensions.  Just search for "Canonical"

These extensions will add a canonical meta tag to the pages to say which one is most important.  This saves all the link juice to just one page, and will clear up most of your duplicate pages.

If you have the .com, you win.  If there is a popular .net, you will get some spillover traffic for your .com.  But if you own "HotLawyer.com", I wouldn't expect you would lose much traffic to "HotLawyer.tv".  Domain brokers can be annoying with their constant offers.