Commas and other extraneous syntactical elements of generative grammar are, in essence, examined as they are in language. So, for example, commas used in numbers greater than 1 with contextually relevant semantic information between them (i.e. "... dog, cat, and parakeet.") deliver something that is considered semantically more similar to the equivalent unordered list:
Code:
<ul>
<li>dog</li>
<li>cat</li>
<li>parakeet</li>
</ul>
... than they are to the keyphrase "dog, cat, and parakeet." In most cases, this would be the intended purpose of creating a semantic list using commas. Using the pipe character (|) in a sentence form is frowned upon by most
modern academic algorithms, because it transmits very little true semantic information, though I have read and heard that it is generally left un-penalized if used in a design context rather than a semantic one. So, for example, this would probably be okay:
Code:
<ul>
<li>dog</li>
<li>|</li>
<li>cat</li>
<li>|</li>
<li>parakeet</li>
</ul>
... while this:
Code:
<ul>
<li>dog |</li>
<li>cat |</li>
<li>parakeet</li>
</ul>
... might not fare as well.
With regards to link building, your best bet is to focus on one keyword or keyphrase per HREF anchor. Just remember that the essence of being able to link in hypertext was to create an easier way of getting to information relevant to the information that is on a page. In most cases, keeping this in the back of your head will lead you in the right direction.