Sometimes, it’s obvious that a blog isn’t a good option:

• The blogger only posts once or twice a month
• The blog doesn’t do Q&As, use guest columns, or review or otherwise write about books
• There’s no effort to engage readers

Surface indicators that the blog is getting traffic that will get your contribution noticed and read include:

• People are commenting on posts
• The blog includes social network share options and when there’s a visible indication of how often content is shared (as it is here, on the left), you can see that people are sharing it
• The blogger is working to bring people back by making it easy for visitors to subscribe by e-mail or RSS feed
• The blog features new content at least once a week

These aren’t rules, of course. They’re just guidelines. Some popular blogs generate a lot of traffic, but not a lot of comments, for example. But they’re a starting point.

Free tools

When you have a lot of blogs to consider — for example, when you’re targeting “mommy” bloggers or parenting blogs — it helps to take the vetting process farther and check the site’s rank. There are several free online tools that help with that. Explore these as you research blogs to visit on your virtual book tour:

• Google Page Rank on the Google toolbar (install Google Toolbar and add the Google PR checker button) will give you Alexa rank, too. Google pages are ranked from 0 (the worst and common for a new site) to 10 (the best). Anything ranked 3 or higher is a good option. This tool also offers the Alexa rank, but Alexa only ranks pages with the Alexa toolbar installed, so that ranking might not mean much for you. (When looking at Alexa ranks, note that a lower number is better than a higher one.)
• The page rank checker at http://www.prchecker.info/ is quick and easy and yields a site’s Google page rank without you having to install the Google Toolbar, etc.
• HubSpot’s Marketing Grader is probably my favorite resource for this, partly because it shows you a list of authoratative sites that link to the blog you’re checking out, which I find helpful. This tool ranks a site on a scale of 1 to 100 — the higher the number, the better the site.
• Custom Rank not only ranks a site, it provides statistics on its trust and authority, too. Smart blogger Bamidele Onibalusi says to look for an overall rank of 30 or higher.

You can also go with your gut, right? Sometimes, you get a feeling that a specific blog is the right fit for the information you want to share, no matter what the online calculators tell you. When that happens, ignore the numbers and trust your instincts.

How do you determine which blogs to visit on your tour? What’s your method?