Stephan Spencer wrote a great blog post on SEO myths and I have to say that I agree with most of them. I just thought I’d make a short mention of one he discusses regarding your meta description tag. Here’s what he says, first the myth:
If you define a meta description, Google uses it in the snippet.
Then Stephan’s answer:
We already learned from my last column (“Anatomy of a Google Snippet“) that this is oftentimes not the case.
I agree. Google does not always use your meta description. In fact, many times it doesn’t.
You have to understand that every web page you write has the potential to rank for several key terms. You can try to optimize a web page for a particular key terms and write your meta description for that term, but just because you attempt to optimize for a specific key terms doesn’t mean your page won’t rank for other terms. You can’t write a meta description tag that will be used for every term your page ranks for. That would be impractical.
What Google actually does is look for the most relevant text to support a searcher’s search query. I that text is the meta description you wrote then so be it. But often, that’s not the case. Google has been known to take text right off of your page and make that the snippet.