Meta description and SEO
Combined with the Meta title, the Meta description is the aspect of your sites SEO you can use to grab users when they search for particular queries on search engines like Google. The Meta description gives you a fair bit of room to work with and if you can’t sum up your page into the space provided then you really should look into how you can optimise the length of your Meta description. As with the Meta title your Meta description will be truncated / cut off if it is too long so making it longer than the available space is pretty pointless. While you Meta title gives a very short headline about your page, your Meta description should expand on the title slightly and communicate in a short clear way unique aspects about your page.
Meta description keywords
In terms of keywords you can include a few; both single and long tail about the page within the Meta description. As with other aspects of your website though don’t keyword stuff, the meta description should be as well written as a paragraph of text and not just have loads of keywords simply separated by commas or similar. Think of how you can sum up your page into a very nice and clear line or two of text that when a user reads it they will want to click the link to your site and learn / see more. Consider also how keywords can be matched within your Meta description by search engines and play about with different orders to the information within.
Meta description and click through rate
It can take a bit longer to perfect your meta description tag than your title on as there is a lot more room to work with and it’s not something that should be rushed. A well planned out and optimised Meta description can greatly increase your click through rate and in turn generate a large amount of traffic for your site. It also helps increase your search ranking positioning which also generates more traffic for your site. So a little planning and optimisation goes a long way to expanding your audience.