Letter C

CAC (Customer Acquisition Cost) - the total cost of attracting one client: advertising budget, team, tools ÷ number of clients.

Carousel - a post with scrolling of several images or slides; increases the time of interaction with the publication.

Chain-of-Thought is a technique where the model reasons step by step before answering. On problems with counting and logic, accuracy is noticeably higher.

Challenge is a viral mechanic with a call to repeat the action and tag other participants or subscribers.

Churn is the percentage of customers who stopped using the product during the period. The main negative metric for subscriptions.

Claude is an LLM from Anthropic. In 2026, Claude Sonnet 4.6 is the best model for long texts and code generation in my stack.

Claude Code is an Anthropic terminal AI agent: writes code, edits files, works with git and tools. On it I collect sites and bots.

Click Fraud is an artificial increase in clicks on an ad by competitors or bots in order to drain the advertiser’s budget.

CM1, CM2, CM3 - marginal profit levels: sequential subtraction of direct, variable and marketing costs from revenue.

Cohort Analysis - dividing clients into groups by date of attraction and analyzing their behavior over time.

Cold/Warm/Hot - three-level audience segmentation based on readiness to buy: strangers, familiar with the brand, ready to buy.

Community management - working with the audience in comments, chats, private messages: responses, moderation, tone. Retains audience between posts.

Competitive analysis - a systematic analysis of competitors: product, prices, channels, creatives, positioning. We look for unoccupied niches, we don’t copy.

Content marketing is attraction through useful content instead of direct advertising: articles, videos, newsletters. It takes a long time to start, but does not depend on bets.

Context window - how much text (in tokens) the model holds at a time: both your prompt and its response. Overfilled - the model “forgets” the beginning.

Conversion Rate - the percentage of users who completed the target action. It is calculated at each step of the funnel separately.

Cookieless - marketing and analytics without relying on third-party cookies. Relevant after blocking third-party cookies in Chrome and iOS restrictions.

CPA (Cost Per Action) - the cost of one target action: purchase, registration, subscription. CPL is a special case of CPA where action = lead.

CPC (Cost Per Click) - the cost of one click on an ad. It is considered a bid in an auction with VK Ads, Ya.Direct, Telegram Ads.

CPL (Cost Per Lead) - the cost of one targeted lead: divide the budget by the number of leads. The main indicator of payback in performance campaigns.

CPM (Cost Per Mille) - the cost of 1000 ad impressions. Used in brand campaigns and media advertising, where the main goal is reach, not clicks.

CPS (Cost Per Sale) - the cost of one sale attracted through advertising. It is calculated: advertising budget ÷ number of sales.

Creative burnout is a drop in CTR and an increase in CPL due to the fact that the audience has seen the ad too many times. Treated by rotation of creatives.

Cross-device - tracking the path of one user on different devices: phone, tablet, computer for correct attribution.

Cross-selling is an offer of related products or services at the time of or after the main purchase to increase the average order value.

CTA (call to action) - call to action: what exactly to do next. One page - one action, otherwise the client does nothing.

CTR (Click-Through Rate) is the percentage of people who clicked on an ad compared to those who saw it. The main indicator of creative performance.

Cursor is a code editor with built-in Claude/GPT that allows marketers to write automation without development experience.

Custdev - in-depth interviews with clients to understand their real pain points, motivations and path to purchase.

Custom Audience is an audience created from your own data: the CRM database, site visitors through the pixel who have seen the advertisement.

CJM (Customer Journey Map) is a map of the customer’s journey from the first touch to the purchase: stages, emotions, touch points and places where it falls off.