I have notice on a couple of sites that when google updates the links in webmaster tools the serps for the website also change. I was of the believe that as google starts indexing other sites that have links to your site then his would have a positve effect straight away on your site but now I am wondering if the serps are effected only when your own webmaster tools account is updated. Footnote- i understand serps can be effected when other sites are updated but when you are in the top 5 and the other sites aren't doing any seo work then I am assuming the changes are because of what I have done!
No. The webmaster tools is just a tool. A useful one. But, think about this... there are millions of websites out there that aren't registered on webmaster tools. PS: some webmasters have no ideea about the service