Increasing website content with a site forum

I run an ecommerce website, I was wondering if by adding a forum, that would be goods for my SERPS?

a lot of content on a website is a great thing and I dont have time to write lots, so therefore users would actually be helping me out.

or would this not help my SERPS at all?

assuming people would actually use the forum.

Well maybe, maybe not, but i would tend to say yes IF you ensure a couple of things:

It must have good content so in turn good users trading/sharing/giving relaible information and not garbage that will entice people to leave asap.

Also you should ensure that it is completely looked after around the clock. Spammers will target you so ensure you have the right team in place to counter this.