It seems that there is a large amount of optimism around about social media ROI this year. However, I remember a colleague of mine saying that there is not, nor ever will be, a holy grail for social media evaluation. I agree that while attempts will be made, it's unlikely we'll ever find a figure that equates to the inaccurate AVE value that was adopted by PR industry to measure editorial coverage.

Instead, we should be looking at a selection of metrics from across the board that are tied to business objectives. If you want to drive more traffic to your website, look at click throughs from social media sources and strengthen those that are working. If building your network is important, look at engagement metrics including retweets or comments. Factor in key messages and you've a strong analysis model for your  business or client.

That's where Postrank comes in. They provide a variety of tools across data services, analytics and for consumers. But my word it's so simple it's fun. Let's take the consumer tools which they state are:

Quite simply Postrank is a master metric for engagement. It tracks posts and scores them against others on the same blog or against other blog posts within the same topic. This isn't just about number of subscribers but about who interacts with the blog and comments, retweets, bookmarks etc. The sheer wealth of sites tracked means a picture can be built and graded.

As bloggers looking to improve levels of engagement or PRs searching for influential bloggers, Postrank is a powerful tool to use and one that should not be ignored. In fact the AdAge Power 150 league table already gives greater weighting to Postrank and other topic specific blog tables such as the Tots100 also incorporate it into their rankings.

Of course tomorrow is a big day as Postrank themselves announce the Top Blogs of 2009 according to their algorithm and rankings so it's going to be interesting to see how this differs from other tables now that engagement is the key factor.