Traffic coming from SEO (Search Engine Optimization) is free, while traffic generated from PPC (Pay Per Click) ads is not free. PPC ads are displayed above organic search results or on the sidebar of search engine pages for search queries related to their topic. Landing page keywords, ad keywords, CPC (cost per click) bids, and targeting all influence how those ads are “served” or displayed on the page.
Forum comments work much the same way as blog comments, except you tend to lack the base post from which to play off. Instead, you need to invest some time into getting to know the culture of the forum, the prominent users, the rules, and the discussion flow. If people generally post one sentence at a time, adding a 3,000 word post will be excessive and may be mocked. If people tend to post lengthy discussions, short posts may have a negative effect. And, like Reddit, some sites may be very rabid about enforcing no advertising.
This is the number of views that you can test each month on your website.It's up to you how you choose to use them, either by allocating all the views to one test or to multiple test, either on one page or on multiple pages. If you have selected the 10.000 tested views plan and you run an experiment on your category page which is viewed 7000 times per month, then at the end of the month 7000 is what you'll be counted as tested views quota.