Webmastering Tools

Recently I have submitted some of my places to G Webmasters tools
immediately they dropped in SE results , probably they are checked
more thoroughly, or loosing a position is suppose to equalize the advantage
you gain from using the tools.
First the tools are useful with checking any technical errors, as googlebot reports unreachable server pages or errors in robots.txt file.
Among the statistics the most useful is the one that shows the position of the site that appeared for the most popular questions people are addresing the search engine.
Sometimes you can be suprised under which keywords you can find your pages.
The rest is very slow.
I use subdomains on freehosts and although some are reached by bots everyday
the change in results appears after a week or so. The cache of the indexed page is changed after a month or even more seldom.
Conclusion : useful tools, but hard to judge now how much is better with using them than without.