Is it necessary for every page to have a meta description?

Matt's answer:

Today’s question comes from the Netherlands. Walter wants to ask, is it necessary for each single page within my website to have a unique metatag description? Great question. OK, so the way I would think of it is, you can either have a unique metatag description, or you can choose to have no metatag description. But I wouldn’t have duplicate metatag description. In fact, if you register and verify your site in our free Google Webmaster Tools console, we will tell you if we see duplicate meta descriptions. So that is something that I would avoid. In general, it’s probably, maybe not worth your time to come up with a unique meta description for every single page on your site. Like when I blog, I don’t bother to do that. Don’t tell anybody. Oops, I told everybody. But if there are some pages that really matter, like they’re your home page or pages that have really important return on investment, you know, your most featured products or something like that, or maybe you’ve looked at the search results, and there’s a few pages on your site that just have really bad automatically generated snippets. We try to do our best, but we wouldn’t claim that we have perfect snippets all of the time. In those kinds of situations, then it might make sense to go in and make sure that you have a unique, handcrafted, lovingly made, metatag description. But in general, rather than have one metatag description repeated over and over and over again for every page on your site, I would either go ahead and make sure that there is a unique one for the pages that really matter. Or just leave it off, and Google will generate the snippet for you. But I wouldn’t have the duplicate ones if you can help it.

by Matt Cutts - Google's Head of Search Quality Team

Original video: