There is still a low take up of Google remarketing features in adwords, but remarketing is a very powerful tool if used correctly. Using remarketing you can target people who have visited your website, but for whatever reason did not purchase or make an enquiry.
You can remarket to these people only making this a very powerful marketing tool.
You can also target people who visited a certain page on your website, so for example if you run an online shop, which sells a wide variety of, products and they visited a page selling golf clubs but did not purchase, you could remarket to these people displaying a special offer on golf clubs. This can have a dramatic increase on conversion rates.
This is only the start of remarketing and there are many more advanced ways you can use remarketing to increase conversion rates, and brand awareness.