So much depends on how you've implemented tags on your site and who your audience is.

It can be tempting to implement tags to try and make up for a broken categorisation and it's tempting to add tags to a page because they mention a topic rather than because it's actually relevant to that tag.

It worth taking a look at your analytics to see if (and how) your visitors are using your tag pages. I've see many sites where visitors just don't use the tags (there too many, they're meaning less, or even they are not obviously links!) and a lot of this depends on just how many tags your using, how meaningful these tags are to people and the relevance and quality of the articles you have associated with each tag.

Have you got internal search set up on your site and are you capturing the search data in your analytics? This can provide some great insights in what people are struggling to find on your site and what they expect to find. It can also highlight areas where your IA isn't working.

(As James mentioned) If your tag pages are indexed, and getting inbound search traffic then segment your non-paid search traffic and look at the bounce rate and other engagement metrics. How valuable is this traffic to you, and how relevant are they finding your tag pages as the answer to their query?

Yes, I've been through this too. My gut feeling here is to focus on your audience and think about how they will consume and share this information.

For example, how can you make it easy for Dave to walk into his boss and tell his boss exactly why he should hire you!

There's absolutely no reason why you can't put the case-study on-line to allow people to read, or at least scan through the document on-line. AND allow them to download the PDF so that it's easy for them to print, read off-line or share around their team/colleagues.

Having the content on a web page also gives you more opportunities to engage your audience (social sharing, even comments etc)

Where PDFs can really come into their own is where you have complicated graphs, drawings that you just can't scale well to fit on a screen, provide enough context and stay legible!

Oh, and make sure that you've got links in your case-study PDF documents to take you to relevant/useful pages on your website.

If you do decide to go down the PDF only route - please do your visitors a favour and provide a really good extract so that they know what they're going to get. I've downloaded too many case-studies that turned out to be rubbish, irrelevant or just blatant marketing bumpf! (Thinking about your audience first can also change the way your approach case-studies and whitepapers!)

The only time I've ever used keywords recently was when a competitor kindly laid out all of the keywords they're targeting in their meta keywords tag!

As the others have said, meta keywords just isn't worth the worry, it's not going to affect how search engines interpret your page* and you're better off spending the time on setting up authorship, open-graph etc.

(*Bing have even said that in some cases they may use the keywords meta tag as an indicator of a spammy site.)

Remember that the title isn't just there to get your keyword in front of the search engines. In conjunction with the meta description it also has to persuade people to click-through from the SERPS and visit your site.

As long as you keep it short, natural and make sure people feel that they'll find what they're searching for when they click on your site it should be ok.

You might also want to think about how your can differentiate yourself from the competition. In the example above "best" is pretty generic.

For a recent project I found optimising for "my keyword + year" got me a chunkier slice of a competitive keyword than if I'd just gone for the keyword alone.

Yes you need to get your important keywords in there, but you've also got to think broadly when you cover the topic on your page and think about the human visitors.

Trust and credibility are important factors and poor copy - especially when it's bordering on spammy, over-stuffed or irrelevant to the searchers intent, is a great way to undermine your website - and that can start in the SERPS!

You are probably better off now worrying too much about any existing URLs with %20's in. Editing these URLs  isn't going to make a massive difference (if any).

Plus, there's always a risk when you edit URLs that you break link that are earning your lots of link equity. If you decide to edit your URLs then you've got the headache of setting up re-rdirects or contacting any linking sites and asking for them to change the links. You'll need to check your internal links too.

The big advantage of not having %20s or other strangeness in your URLs is that it does makes them more meaningful are shareable by human beings. You really don't want to have to read these out or print them on the side of a lorry or brochure!

So, I'd suggest it's not worth worrying about, but may depend on your circumstances (such as the age and the number of links). If it's a new site with no links to these pages and there aren't many of them then you may want to do it just to keep things tidy/consistent.

If you've got more than a few, with inbound links to them then you're probably better off using your time elsewhere.

Got to agree with EGOL here. As soon as you start boiling articles down to numbers like this you're going to lose. There's no magic formula that will protect you from bad copy.

Ignore the links for a moment. Think about how your blog post is going to help promote you business/service. Is it being posted somewhere your target audience are going to read it? Is it useful/interesting to that audience. What's the one thing above all else that you want the reader to do once they've read the article...

Without taking a look at the site and the content you've got it's hard to talk specifics, but you might want to test removing the links from the product pages to the blog. After all, you want people to add the products to their cart - not drift off into the blog.

(Of course. Depends on how well the blog supports people purchasing decisions, and promotes your offerings etc,)

In one of your response to Greg you say: "if there are not many reviews available for a product but my client has reviewed the product and posted it to their blog, Google will prefer that to the product page itself."

This makes me suspect that it's just the weight of relevant copy on the page that's causing Google to view the blog page as more authoritative. I'd also guess (gut feeling) that having links from your product pages to your blog is also going to make is less clear to Google which should be the authoritative page.

As Chris and Houses have said, the focus should really be on what works for the readers of your blog.

In my experience, tags don't tend to work very well for people .As long as you've got good navigation, some well thought out categories and site search then this is enough.

The problems for search engines is that these tag pages can create lots of duplicate content if not implemented properly (just like categories). They'll also increase the number of links on a page.

If you want to surface related content, then in-line links to older content in proper context is better, and/or some related content listed at the bottom of the article can work.

It does depend on the goals for your blog pages through. Links to related content can decrease the number of comments that get left.

The question you need to ask is whether people using your tags? What does your analytics tell you? How many people are viewing tag pages and what are they doing next. How many people leave your site from a tag page, or a page following a tag page? Is this higher than normal?

If you're going to tag articles, don't just tag them because the article mentions you keyword. Try to think along the lines of "if I click on this tag, and look at this article, am I going to find what I expect". Try to think about topics of interest rather than keywords.

Fewer is better than lots. The more options you give people the more friction that causes - too many and people will just ignore it.

One solution would be to put this supporting information onto the product pages (and 301) but...

This might be more of an opportunity than a problem!

Not everyone searching for a product is actually looking to buy now. Recognising that different people will be in different stages of the buying cycle and creating content to support and more these people towards your sales pages.

Make sure that your blog posts also sell - both the products and also your offering/usp.

As well as just having a link - make sure it's an obvious call to action with a clear proposition too. if they want to go ahead any buy the product - give them a reason why they should buy from you.

Your blog posts might provide you with a great opportunity to communicate the added value, authority and trust in your brand to your prospective customer.

As well as having a link at the bottom - make sure that you've also got a clear and obvious "looking to buy now?" CTA above the fold for those competitive/impulsive people who do want to buy now!

What's happening when people arrive on your blog pages, how long so they spend on them, are they moving on to your product pages?

Is there a difference in the conversion rate for people entering via the blog and going on to your product page vs those that arrive directly on your product pages?