The Internet is abuzz since Google quit providing keyword data to site owners three days ago. Since then, SEOs and veteran Internet marketers have offered their advice on culling actionable data from multiple sources so that website owners can keep growing their businesses.
One SEO even called Google out on anti-competitive practices.
I'll leave that for others to discuss. What I want to draw your attention to is a tool that webmasters have had at their disposal for a long time. You may consult it occasionally, or every day, but you should consult it now more often. It's called Webmaster Tools.
If you look inside your Webmaster Tools account, you'll find a link to Search Traffic reports on the left side of your screen. Click that and then click on "Search Queries." While this isn't perfect, you can use this tool to determine the most popular keywords searchers use to find your website. What's beautiful about this tool is it will tell you how many impressions that keyword has received and how many clicks it received during your time frame. Also note the average position of that query phrase in search results.
Is this information perfect? No. Is it usable? Yes. You can use this information to plan your keyword SEO campaigns and to judge the value of your keywords for searchers. Combined with other data tools, you should still be able to make fair judgments about the effectiveness of your SEO campaigns.