Search:

Definitely, you can if you have a large set of communities. because you promote other products or services. if promotions are done via you at that time you will succeed you marketeting.

Check your google webmaster-> manual actions - it shows if google penalty your site.

-> performance - it shows a which search query was suddenly decreased.

Cloaking is a blackhat SEO technique. it shows different information when the user tries to know something online what they are seeing. Actually it works on redirection method.

If you update your website same keywords on more than one page it affects your website performance which is called keyword cannibalization. it will down your ranking on both pages

No follow links don't help you with the ranking process. it can help you only for indexing process