Welcome to the Q&A Forum

If you have a relevant category I would redirect them there.  If not, just send them to the homepage.  You don't want to see 404s and neither do the people visiting your site.

Depending on your business I would think less of mobile SEO and more of building your local citations.  Remember that most people who are using tablets are using it for simple things such as finding a perfect restaurant or finding things to do.  Even Yelp is tied to Apple's new Maps system.
Make sure that you're on every review site possible such as Yelp, Urbanspoon, Google local, G+, and all the social networks that are relevant to your niche.

With questions like this, I tend to look at it not from Google's point of view but from a person's point of view. The spiders are getting smarter after all and Google always says to write content and create websites for people not the Spiders.

So to answer your questions, you might want to ask yourself these questions:

• How am I supposed to know that the links on my website are broken, because a site I was linking to is now down?
• How do I know that the domain I am now visiting was down for a month or even a year?
• How do I know said blog is being used for black hat purposes? It it has relevant content and helps me, that's all that matters.

It's up to you, but I have to agree that using different emails might be the best way especially if you think you might be losing the accounts later on.  
Handing them over might be an issue in the future if you only use one account.  Who wants an angry and nasty client, after all?

As I said you can setup a new view with an include Filter to only include your blog directory and view the demographic data through that.

Another method you might try is under Admin > Content Grouping, This will allow you to group blog posts together and when setting up the report, you will be able to select the Content Group under Filters.

https://support.google.com/webmasters/answer/35255?hl=en

The Content Keywords page lists the most significant keywords and their variants Google found when crawling your site. When reviewed along with the Search Queries report and your site's listing in actual search results for your targeted keywords, it provides insight into how Google is interpreting the content of your site.

The significance of each keyword reflects how often it's found on your site's pages. Click each keyword to see a sampling of pages on which it appears. Both keywords and their variants are listed in order of frequency of appearance.

If unexpected keywords, such as "Viagra", appear on this page, this could be a sign that your site has been hacked.

Do you want to provide a URL?  Google search a page and view the cached version, it definitely sounds like something is injecting these words and likely links as well.

All of the responses here are good, but we also want to throw out the fact that as a company, do you know if your brand is a successful brand.  We can all come up with ideas for companies but are they really money making worthy.

We have people who have worked on both sides of the coin, agency and in-house and I can say as an agency person, I see a lot of people who are afraid of really doing what they need to be doing to win the online battle.  How are you marketing to your clients currently? Are you knocking on doors?  Is your business even really marketing online?

I agree with Oleg. In theroy it's a great tool, but we've seen issues with it as well. It sometimes doesn't always work and it somtimes says things are "broken" when in fact the listings are correct.

What we suggest is that you use it as  a "brain storming" tool for where you should build links to your local listings.

One of our in-house marketers was in a similar situation about a year ago.  Here's what we can say.1) Find out as much information about the company as you can and take a look at their analytics.  Does one website drive traffic more than the others?  Is one more important to the client?  Find out what drives the revenue of the company and start there.  It might be more important to invest money and time from in the top website and trickle down...
2)  Subdomains would probably be the best, but that's not always an option according to the client, we understand.
3) Are all of these websites different brands or just different websites?  For example Burgers.com and Hamburgers.com.  If they're the same site, you definitely need to change them at least cosmetically.  Make sure that they have different call to actions, etc.  Think of it as an A+B test and go from there.  Be creative.  Make one website green and one blue, and always keep in mind duplicant content.

There is always a chance of something going wrong.  Just try to have all your ducks in a row.  Make sure your redirects if any are setup and ready to go and make sure everything on the new site is better optimized and more SEO friendly and you should not have any problems.

If you hover over the tab in Chrome it will show you the full title.

Fabrizio,

Obviously it would be a concern if another company thought you were stealing their content and infringing upon it, without at least a link back, so you might want to reach out to those companies before you post any of their content.

My suggestion would be to look at what, GDGT.com is doing it sounds like what you want to do is what they're doing in the electronic space.

Bob,

I would suggest creating great content and then using social media and email to spread the content like fire. A term that we stole from Jay Baer is content is fire and social media is the gasoline to that fire. For example why don't you add an important piece of content to your email signature or email it to a few influencers in the community. They might find it important and want to share it with everyone or even link to it.

If you're new to SEO check out the Beginner's Guide by SEOMoz, that might help you out.
http://www.seomoz.org/beginners-guide-to-seo

Also it's worth pointing out that the guy who wrote the testimonial has a PR of 1, which is just one level above the 0 where all sites begin at.

My feeling based on looking at the titles is that the pages have at least someone different content.  I would think the company was trying to target some area based keywords somewhere on page 2.  Does that page get targeted traffic based on those keywords?  If so I would keep it alive, as a blog post if you wish, as redirecting it would lose that traffic.  If it gets no traffic and is not successfully targeting any long tail keywords then just update the internal links and redirect it to page 1.

Fix the alt and title tags on the images, and while you're at it rename the images so they are relevant as that was likely not done. As far as meta descriptions, that will not help you rank, but can affect clicktrhough rates in the SERPs. My thoughts are you probably have a lot more cleanup to do and adjusting meta descriptions should be a lower priority task.

I agree with ameli, SEO has not changed that much from the early days it's more that the tools have changed. Twitter has turned into Buffer and Hootsuite, G. Analytics has changed into some weird combination of Analytics, Raventools, and Moz, and so on.

It's all changing on an everyday basis but the basics still remain the same. Create an awesome website, engage with your customers online, and care.

Are you trying to check a lot at once? if not, just use the site: operator, i.e. site:abc.com/page

Ouch!  Our first thought is that having a lot of choices sounds ugly and frustrating, from a user experience side.  Remember you don't want to give your customer too many options, you want to guide them through the process and watch them through a conversion funnel.    
Why don't you just create landing pages and add those to the header?

For the first question, if you have the time to make all the pages and are willing to do so I think it's a great idea.  In most cases getting content right away is the hard and time consuming part so a lot of people will instead use blog posts to target the long tail keywords.  I can easily see several posts about construction, maybe an unboxing of a kit, and a color chart sounds like a great infographic piece.

For part 2, google lowered the value of keyword rich domains long ago.  Search in any major market for anything and I'm sure you'll see many many sites ranking above those that are keyword rich.  I'm not saying being keyword rich doesn't help, but for instance search seo and notice some of the top results will be wikipedia, moz.com (which admittedly used to be seomoz) and searchengineland.  These aren't keyword rich and they still rank well, if you like the name then that's what you should go with.  Tell the seo company that if they want a keyword rich domain then they should make it into a second microsite and can build links to both, but make it clear to them that the main focus should be on the main website.