Do you have the resources to create unique content for all those pages? Because adding 500,000 pages of duplicate content will absolutely damage your site.

How competitive are the keywords you're targeting? If you're trying to get onto page 1 or 2 for something like "women's shoes," that could take years. On the other hand, if you're targeting something like "cthulhu pajamas," you could end up on page 1 right off the bat.

Remembering that rank is a combination of relevancy and authority. It's pretty easy to make a site that's relevant for a keyword, as long as you know the basics of KW density, title tags, img alt tags, and so on. At that point, Google will try to determine how authoritative, trustworthy, and popular you are. Is anyone linking to your site?

The main concern is whether or not the spider can read the HTML. If something's broken, the spider may get confused. It's a good idea to check the site's W3C compliance and correct what you can, but I'm certain the search engines don't ding you if you're not perfectly compliant.

The real problems with bad HTML are load times and cross-browser compatibility. (Although, frankly, great HTML can have cross-browser compatibility issues, since IE still refuses to get with the program.) Make sure the site looks good in all major browsers.

I'm surprised no one has mentioned the obvious: The Google AdWords keyword tool assesses competition based on AdWords, not based on SEO. A high competition keyword is a keyword that many advertisers are bidding on. It's common practice in AdWords to bid on low-volume high-conversion keywords. Those can actually get you the best ROI sometimes.

I can't see why they wouldn't.

They should count for Analytics purposes because obviously that person was looking for the company in question, even if they couldn't spell or hit an incorrect key on the keyboard.

Also, Google is returning 7-result pages for queries like "ammazon," "jc peeny," etc. so obviously it knows what the misspellings mean.

Is your company a local one, like a pizza place or a shoe-repair business? If so, then people who are in your industry but not in your city are not actually competitors. If you're both national companies in direct competition, though, I find it hard to believe they'd accept your guest post.

The category pages definitely don't look clean and professional right now, and that will impact conversion rate. You have enough copy on the category pages to establish relevancy, so I would be extremely surprised if your rankings went down after you stopped showing the product descriptions on the category pages.

If you're hesitant, would it be possible to test it both ways? Choose a couple of categories and pull the product descriptions off them. See what happens to their rankings and traffic.

Set realistic expectations for your client. It's fine if that's how they want the site to work, but explain to them that search engines primarily read text; without much text, the search engines will have a harder time figuring out what the page is about. Also explain their options: They can have more text on each page without compromising the design, by using tabs, collapsible divs, etc. Figure out whether or not visitors want more text on each page. If you can make that case, they might be persuaded.

Meanwhile, focus on the things you can control, like title tags and img alts. Then focus on linkbuilding. That should be relatively easy -- fashion is popular and has great potential for compelling content. At least you're not working for a plunger manufacturer.

If they have videos, they could add transcripts in a collapsible div. That also address accessibility and general user experience. After all, if someone is sneaking a peek at the site at work, they probably don't want to have the sound on for videos.

I think you are being blinded by your bias, yes.

If you, the web designer, insert a link to your site into the footer of all the sites you design, that is not an editorial link. It's not a link that the site owner created of their own volition because they think it's valuable content. In fact, if a company is hiring an outside web designer, they might have no idea how to remove the link from their footer. They might not even notice it.

The search engines know all this, and it's why they don't like footer links. They are well aware that web designers, Wordpress theme developers, and so on have been using this technique for years.