Question and Answer site https://www.quora.com/ claims 190 million monthly unique visitors and is a powerful source of leads, traffic and inbound links to help with your SEO.
Start with your niche, set up your profile to reflect that, search for it, click 'follow topic' and assuming your profile is set to send you notifications, you'll see all the questions in your niche.
The 'niche' part is important, you want people to see you as the leader in your niche so it's obvious to them they should talk to you. Answering broad lifestyle questions for kicks isn't going to bring an ROI.
Get it done by: http://www.surgemarketing.co.uk
For: .. depends on our solution for you, but Surge Marketing gathers ideas for content, then maximises their worth through social/blogs/PPC/PR. Quora is a source of ideas