Are Facebook groups important to marketers ?

a good group can be possible thro only a good page;  and good fan followings ;so if the page have great supporters a group will be a great asset for the brand

Nope. Pages yes, but not groups.

التسوق عبر وسايل التواصل الاجتماعي اصبحت  الان  مثيره  للاهتمام حيث وان  معضم  الاصدقاء  والمتعابين يصوتون بالاعجاب والمتابعه  لكل منشور سواء منشورات  تجاريه او  غيرها   فباعتقادي انا  عني وعن نفسي انها وسيله اصبحت  مهمه للغايه بالنسبه للاعلانات التجاريه والشخص المستضيف اغلب الاصدقاء والمتابعين والمنظم لاكثر من مجموعة وبطريقه  فنيه  دون ازعاج سيحقق نجاحا  باهرا   وياتي بنتايج  ايجابيه ومبشره واكيد وكلنا نعرف ذالك

Face book has around250 million users yes it is a source of creating lot of noise about your product and sure will be a word of mouth and means of marketing your product moreover if your brand is globally available the audinece will be wide.Still if it is restricted to a particular geographic location then you have to expand your contact list on FB

Facebook is the most important pool nowadays.. Just do the right activities and you will get outstanding results.

I don't think so, because facebook groups created for conversations or share things between a small group of people for example family, teammates or coworkers also it dosen't include such options like insights, targeting specific people as fan pages.