Which is the best forum submission website with DA / PA?

How to decrease the loading time of the website?

What are Doorway Pages?

What is Cloaking?

What are rich snippets?

What tools are useful from the perspective of seo techniques?

What is Google Penalty?

What is Google Algorithm?

What is Sitemap ?

Is directory submission still working?

What is Blog Commenting and what is the value of blog commenting SEO ?

Please describe robots.txt, do-follow and no-follow?