Hi Ananda. This would be the first question I am trying to answer today.

While it's true that OzBargain has a significant online traffic in Australia -- a country of merely 23 million people mind you, so "huge" is probably not true in the global scope -- it took a long time to gain the popularity and the size OzBargain is today.

If you ask me whether there's any tips or short cuts to drive traffic, sorry I have none. Everything I got can be found in the Online Business rulebook 101 --

• Engage with your users. Listen to them. Sure they are not always right but often they become the driver of the business. If you have been with OzBargain over the years you'll find how we iterate and take suggestions implementing new features. Feedbacks from our users are crucial.
• Iterate, and iterate fast. We are aiming to bring out new changes every week -- new function, UI tweaks, rule changes, etc. Again feedback from users as well as testing/analysing here is important.
• Know your goal and don't get side-tracked. At OzBargain our goal is to build a large community for the consumers. All our features and development centred around how we can facilitate our users in their quests to share, discuss and discover the latest bargains. "Money" is one major side track I found, as every week I'll get emails from media agencies, ad network and some dodgy operators trying to lure you with financial incentives to integrate with their solutions (which often aren't what our users want). Stay focused.
• Being persistent. I am not a growth hacker, but what I learnt is not to lose heart when you still don't get much traffic one year after launching. Actually OzBargain's first two years were pretty boring. However continue to engage with users, listen to feedbacks, iterate fast with development and stick your goal -- you'll get there eventually.

In terms of traffic source OzBargain has always been

• ~50% organic. Mostly Google yes SEO is important although never over-do it.
• ~10% referral. Whirlpool and Facebook being our biggest referrers. Key is generating enough interesting content and providing useful service, other people will mention you on forums and social networks.
• ~40% direct. When you have a group of die hard users who would bookmark you and visit your site daily :)