The Description Meta Tag works in a unique way. When your Page / Site Blog gets thrown up on Search Engine findings it is the Description Meta Tag that gets shown as snippet. If written well then it is this that brings you click through. So if your Description Meta Tag is compelling enough then be sure that your click through rate via the Search Engines is a certainty.
The other important Meta Tag is the Page Title. This directly is seen on your Search Engines in bold. It is the result of search words used by your target audience.
Both, Description and Title Meta Tags together form the text that you read on Search Pages. If written well they will induce and encourage readers / searchers to click.
Your description cannot be longer than 160 characters in case of Google.com for instance. After 160 characters your text will be truncated.
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