It has long been popular to post on forums, blogs, et al

But if you provide the facility on your own website to get consumer interactivity then you can add

Comments Features
Upload Text
Upload Images

etc etc

It's not rocket science but it does increase your viral marketing options and of course it in most cases will provide you with additional much needed original content

Try it if you site needs a boost (most do nobody turns down new traffic)

Start by filtering the uploads by using an approval/editing gateway

Then you can edit the content prior to approving and going live

We have been doing it on one site for over a year it has been a very very solid assured way of not only building the site, but it has given the site broader reach and penetration in different subjects and global destinations

At the same time with commitment of time and effort your site will gain solid hold with new uploaders/UGC providers, carving out and establishing your site in an expanding and viable niche sector of the web