1. If your website has a penalty Google will probably inform you in your Google Webmaster Account. Why? So you fix it.
2. If your website is hacked, Google will even try to email you to let you know, but the site will be removed from the index until you fix it.
3. Your Yahoo rankings can get a quick and fast boost if you submit your website to the Yahoo Directory. Why? Yahoo prefers sites that are listed in their directory..

Once very simple (only Yahoo was worth submitting), the science of submitting sites to directories has become increasingly complex. There are numerous softwares, sites and services that take care of (or promise) submitting your site to the millions of directories existing today.

Unfortunately, the promise of "Be listed in 10,000 directories with one click" is blatantly false. If you want to be listed in PageRank Zero directories, an invitation to being banned, go ahead. And do not forget to give them a real email, for them to spam you forever..