For example, let's say you operate an e-commerce business that sells kitchen supples. You might create a “toaster” remarketing audience based on people who visit the pages of your site where you sell toasters. That way, you can show these specific visitors highly targeted display ads that market your toasters. You already know they are in-market for toasters, and now you can draw them back, perhaps with a special offer like "free shipping."
This situation happens most often when an organization has multiple AdWords accounts that all create campaigns for the same website. A GA account can only be associated with a single Google AdWords account. If a campaign that generates the visit belongs to an AdWords account which isn’t linked to the given GA account, the visit will show up with the keyword “not set”.
No, unfortunately we can not guarantee that the absolute safety of Google Adsense Traffic. This is because we have seen instances in which websites were penalized for receiving large bulks of traffic (and clicks) to their Google Adsense ads. Therefore, if you use it, we strongly recommend you to use it in moderation and in conjunction with other traffic sources. More information >>