Audiences are groups of users segmented in a variety of ways. Most often audiences are used in remarketing. Audiences can be created based upon specific pageviews, time spent on site, pages per visit, and more. Similar to keywords, audiences are bid upon based on relevance. For example, advertisers may bid more to remarket to shopping cart abandoners vs. homepage viewers.

3. General on-site optimization. On-site optimization is a collection of tactics, most of which are simple to implement, geared toward making your website more visible and indexable to search engines. These tactics include things like optimizing your titles and meta descriptions to include some of your target keywords, ensuring your site’s code is clean and minimal, and providing ample, relevant content on every page. I’ve got a huge list of on-site SEO tactics you can check out here.
To show an ad in PPC or Paid Search results, marketers create ads and then bid on specific search phrases for which to show them. These pay per click ads will then appear above and below the non-paid organic search results, and you’ll pay the search engine a small fee every time a user clicks on your ad, regardless of the total number of times the ad was shown.
SERP stands for Search Engine Results Page. A SERP is the web page you see when you search for something on Google. Each SERP is unique, even for the same keywords, because search engines are customized for each user. A SERP typically contains organic and paid results, but nowadays it also has featured snippets, images, videos, and location-specific results.
PageRank has been used to rank spaces or streets to predict how many people (pedestrians or vehicles) come to the individual spaces or streets.[49][50] In lexical semantics it has been used to perform Word Sense Disambiguation,[51] Semantic similarity,[52] and also to automatically rank WordNet synsets according to how strongly they possess a given semantic property, such as positivity or negativity.[53]
Generally speaking, “ad position” is influenced by the amount you are willing to pay (max CPC bid) and the relevancy of the ad to the keywords in your ad group (Quality Score). Quality Score is a numeric representation of the relevancy of your ads and keywords assigned independently by both Google and Bing. It is important to note that only Google’s Quality Score impacts ad position currently. Bing’s Quality Score serves only as a guideline to improve your ad/keyword relevancy. We will discuss Quality Score in further detail in Part B.
When PageRank leaks from a site via a link to another site, all the pages in the internal link structure are affected. (This doesn’t always show after just 1 iteration). The page that you link out from makes a difference to which pages suffer the most loss. Without a program to perform the calculations on specific link structures, it is difficult to decide on the right page to link out from, but the generalization is to link from the one with the lowest PageRank.

Google and Bing provide basic conversion tracking within their ad platforms, but not for revenue. Take a look at Google Analytics for a free tracking system that will let you measure conversions from all PPC sources and let you track traffic, revenue, and conversions. If you’re a leads based business, you may also want to consider a scalable CRM or customer relationship management system like HubSpot, which allows you to specify when and if a lead became a customer, so that you can clearly identify which ads are turning into real revenue.
Interests are very similar to Topics. In fact, they are the same themes. However, the key difference is that Topics target websites and Interests target users. Google gleans user interest based on browsing history or self-selected interests if they’re logged in to their Google account. This allows your ads to appear on whatever site someone with your targeted interests is on, even if that site isn’t related.
Depending on the number of Web pages that contain a particular word or phrase, a SERP might show anywhere from zero (in the case of no matches at all) to millions of items. For example, entering the phrase "complex-number admittance" into the Google search engine yields few results. In contrast, entering the single word "hurricane" yields millions of results.
To prevent users from linking to one version of a URL and others linking to a different version (this could split the reputation of that content between the URLs), focus on using and referring to one URL in the structure and internal linking of your pages. If you do find that people are accessing the same content through multiple URLs, setting up a 301 redirect32 from non-preferred URLs to the dominant URL is a good solution for this. You may also use canonical URL or use the rel="canonical"33 link element if you cannot redirect.

Informational searches are those in which the user hopes to find information on a given topic, such as Abraham Lincoln. It wouldn’t make much sense to place ads or other types of paid results on a SERP like this, as the search query “Abraham Lincoln” has very low commercial intent; the vast majority of searchers using this search query are not looking to buy something, and as such only informational results are displayed on the SERP.

Webmasters and content providers began optimizing websites for search engines in the mid-1990s, as the first search engines were cataloging the early Web. Initially, all webmasters needed only to submit the address of a page, or URL, to the various engines which would send a "spider" to "crawl" that page, extract links to other pages from it, and return information found on the page to be indexed.[5] The process involves a search engine spider downloading a page and storing it on the search engine's own server. A second program, known as an indexer, extracts information about the page, such as the words it contains, where they are located, and any weight for specific words, as well as all links the page contains. All of this information is then placed into a scheduler for crawling at a later date.