Have you reviewed the list Theo shared? It is really fantastic.

Overall I am not a fan of directories. If I found a directory that matched the description you offered, then I would definitely be interested in it. (Who wouldn't?).

Be careful that if you do find a directory that requires payment, you are paying for your site to be reviewed as opposed to paying for addition to the directory. I would be stay away from any site that offered a money back guarantee as Google may view that as a paid directory submission.

Another site that falls under the category of a directory would be the BBB. Unfortunately their price range is somewhat similar to Yahoo.

You should check out Google Places as well.

There are three directories I look to for clients:

1. Dmoz. It's free but can be challenging to get accepted.

2. Yahoo Directory. It is about $350 but they will cover your site in their world wide directory.

3. BOTW. The internet's oldest directory. $150.

Otherwise I look for directories specifically related to the site's location or the products and services offered.

As Dave shared, the W3C is the official organization for determining the validity of code. Generally speaking, you want your code to be valid.

If you want an area to be a click-able link try Maximise's suggestion.

Neither option is valid HTML. Browser behavior and crawler behavior would be unpredictable.

The code would be something like:

Keword 1
  

The short answer: in the context of your question, font size has no effect on SEO. You can offer a page in any font-size ranging from 10 - 14 and it would not make any difference.

As the others suggested, your site's readability will impact the user experience. As long as your site is properly coded, browsers have the ability to change font-size to larger/smaller. It would be a nice feature to offer users a widget to allow them to change font-size to their preference.

The font-size may affect factors such as click-through rate, time on site and so forth. It does not directly affect SEO but could indirectly affect it through the user experience.

I wouldn't go so far as to call the extra links spam. They are not helpful to SEO. They just add extra links to your page.

If you sincerely believe they are helpful for users, then leave them. Otherwise, I would recommend removing them.