I haven't used the Google Webmaster Tools at all. What's the advantage / disadvantage of adding a site to be tracked?
1 really big advantage: it gives you obvious feedback about what's going on with your website. Let's say you make a bonehead move and disallow your website in robots.txt. In the old days you'd have to wait a while until all your SERPs dropped to figure it out! Now you'd know immediately based on status reports in GWT.
It allows you to see any warnings or crawl errors, and you can also submit sitemaps and see crawl stats for your site.
Nope. You can set the preferred domain one in there. I'd use one version, 301 redirect it, and set it in there to be on the safe side. It's always best if you refer to your domain with one unified URL.
Yeah I added it as domain.com but I have 301 redirect to www.domain.com. I'll delete and re-add in GWT.
Basically, this tool can helps track your pages on Google... also, it can helps find broken links, errors etc.... helps with sitemap, robots.txt... it's not "a must", but i would recommend using GWT
Top search queries, change crawl rate, find what pages google says are a 404, submit your sitemap.. Google Webmaster tools isn't so bad .
Google webmaster tool helps a lot in terms of monitoring your site, rankings, crawl rate, backlinks, site links and etc.