A meta description tag is an HTML snippet placed in your page's <head> section that tells search engines what your page is about. It looks like this: <meta name="description" content="Your summary here">. Google pulls this text for the snippet shown under your blue title link in search results, though they'll rewrite it about 63% of the time if they think another passage better matches the query. The tag itself carries zero direct ranking weight since 2009, but it dramatically affects whether someone clicks your result or your competitor's. A well-written meta description can lift CTR by 5-15%, and sustained CTR improvements do feed back into rankings as a user satisfaction signal. Think of it as ad copy for organic search. Keep it between 155-160 characters to avoid truncation on desktop. Mobile cuts off around 120 characters, so front-load your hook. Include your target keyword naturally because Google bolds matching terms in the snippet, drawing the eye. Skip keyword stuffing or generic statements like "We offer the best services in Ottawa." Instead, state the specific benefit or answer: "Ottawa SEO Inc. runs 500+ domain portfolio with 10+ years ranking data. Book a free technical audit." At Ottawa SEO, we write meta descriptions after the page content is final, not before. We test variations when CTR lags expectations, especially on commercial pages where a 2% CTR jump on a 10,000 impression/month term means 200 extra qualified visitors. We also skip meta descriptions entirely on long-tail blog posts where Google's auto-generated snippet from the opening paragraph often outperforms our manual summary. Watch out for duplicate meta descriptions across pages. Google sees it as low-effort and you waste the chance to differentiate each result. Also avoid exceeding 160 characters unless you're deliberately targeting only the first clause, letting Google append context. If you see your descriptions constantly rewritten, your content likely doesn't align with what users actually search for, and the meta tag is just masking a deeper relevance problem.