I would like to know how useful are the links from different article directories, now-a-days in the age of penguin 2.0??

Can anybody explain to me what is the importance of deep linking & why we should do it ?

Sandbox effect of a website means it is not indexed by the search engines. If your site is new then you will not found your site in the search results which means that your site is not out of the sandbox yet. Or, it may happen that you are penalized by the search engines and its is not appearing the search results.

Some says facebook promotions are useless. I want to know is it really possible to promote & increase traffic via facebook??

Bing bots are unable to crawl my site. I have submitted my site through bing webmasters tool one month ago but no crawler have crawled since then. It does not says any error like 404 or 301, but still no crawl information.

Does anybody have tried the google keyword planner? How is the experience of it?

Does links from different social networking sites matters?? Can they increase my search engine rankings??

Where i can add my site's url to my profile ??

Can any body tell me that what is a keyword frequency ??

I was wondering what does w3 total cache plugin for wordpress does ??Does it helps for better SEO??