The Interest report is broken down into three different sections: Affinity Categories, In-Market Segments, and Other Categories. Together, these insights show you what your audience is interested in. When used in conjunction with conversion tracking, you can see what your most valuable audiences care about.
Audience > Interests > Affinity Categories
Affinity Categories allow you to learn about your audience based on what they’re interested in. This insight is designed to help you discern how to reach more users at the top-of-funnel: those at the very beginning of the customer journey who may not yet be aware of your brand or products.
Audience > Interests > Other Categories
Other Categories provide a more granular look at affinity categories. For example, an affinity category may tell you that your audience is interested in sports, but through this view, you can dig deeper to discover that it’s actually team sports/soccer that your audience is most interested in.
Other Categories also shows what Google Analytics calls a Life Event. Life Events can include things like starting a new job, moving, graduating college, or getting married. Let’s say that one of your most valuable audiences is people who are starting a new job. Knowing this information is incredibly useful in crafting content strategies to attract more visitors that are going through this life event. You could also use this to inform ad targeting (e.g. creating a Google Adwords campaign, or group targeting people who are starting a new job).
Audience > Interests > In-Market Segments
In-Market Segments give you insight into users' purchase intent. This insight is designed to show you how to reach people that are further along in their purchase journey: they're actively researching and comparing products and are more likely to purchase. Google recognizes and categorizes intent by looking at the ads people click on, the content of the web pages people visit, as well as the frequency and recency of those visits.
Language reports
Geo > Language
The Language report will tell you the languages spoken by the users who are visiting your website. Google determines language based on the browser’s location and language settings.
This report can show you how you’re performing in the language(s) you're actively marketing in, as well as uncover opportunities for localization. For example, let’s say all your marketing material is in English and your primary markets are English-speaking locations. You would undoubtedly want to segment your website visitors to see how you’re performing among English-speakers. This can be done using Advanced Segments. In the demographics section under language, you can add “en.” This will create a segment for all users who visit your website who Google has identified as English-speakers.