SEO for standard websites is pretty straight forward. I happen to be working on a website redesign (in Drupal) which presents Linguistic resources both published and unpublished. I recently came across two specialized SEO options which are useful:

1. Integration with Google Scholar
2. Aggregation with OLAC

Google Scholar

Google Scholar’s page on getting data into Google Scholar:http://scholar.google.com/intl/en/scholar/inclusion.html

Biblo, a module for drupal which handles bibliographic data had something here.

This blog also has an interesting write up: http://blog.reallywow.com/archives/123

OLAC Search

This means implementing the OAI-PMH protocol so that OLAC can harvest it.
I am not sure how this is done exactly… but here is the link: http://www.language-archives.org/.