All three major search engines - Google, Yahoo and MSN/Live - provide a suite of webmaster tools that are useful for SEO. Using these tools, you can tell the search engines about your website, troubleshoot problems that are found by their spiders and instruct the search engines to remove a deleted webpage for example. Here are some of the features I’ve found useful:

1. Google Webmaster Tools
- submit sitemaps.
- web crawl errors.
- content errors, e.g. duplicate title tags.
- search words that return your website in the results.
- anchor text used to link to your website.
- incoming links; more accurate than using “link:mydomain.com”.
- set preferred domain, i.e. www or non-www, to avoid canonical problems.
- remove URLs of old pages that no longer exist.
- set geographic target for better priority for local searches, e.g. on google.com.sg.

2. Yahoo Site Explorer
- submit sitemaps.
- re-write dynamic URLs.
- number of indexed pages, i.e. “site:mydomain.com”.
- number of incoming links, i.e. “link:mydomain.com”.

3. Live Search Webmaster Center
- submit sitemaps.
- last crawl date, domain score (sorta like Google’s Pagerank), indexed pages, blocked URLs.
- problems due to missing pages, blocked URLs, dynamic URLs, unsupported content.
- number of incoming links.
- number of outgoing links.

Have fun! :)