Quite a few authors have set up fan pages on Facebook, and the new Google+ has tech heads in a swoon. But I still spend most of my social media time away from my blog on Twitter.

Twitter remains the nervous system of the social media world and, increasingly, of the regular media world, too.

I’ve long thought of Twitter as a kind of utility, like gas or electric service, but piping in the real-time thoughts, jokes, links, wisdom, meetup plans and everything else being blasted 24/7 into the Twittersphere.

However, remembering that book publishing is a business leads me to wonder exactly what I’m getting for all this engagement. Granted, Twitter is the easiest place to meet like-minded people, to get the latest links of interest in your niche, and where content can go viral.

Even Apple has voted for Twitter by integrating the service right into the upcoming iOs 5 for the iPhone and iPad. This will allow all apps to be Twitter-enabled.

I’ve rounded up a bunch of websites and services that provide Twitter tools can help you evaluate two important aspects of using Twitter:

• The effect your marketing efforts are having,
• The profiles of other Twitter users

Some of these services have both free and paid capabilities, but I’ve avoided anything you have to pay for. Here are the free Twitter stats and analytics tools with a few notes. Enjoy.

Twittercounter.com

Twittercounter shows statistics in attractive charts that are customizable to some degree. The site also offers predictions on when you’ll hit certain targets, and follower badges that update in real time for use on your blog or website.

Tweetreach.com

Tweetreach offers a great analysis of your last 50 tweets so you can see what your actual reach is. Here you can see it’s calculated my last 50 tweets reached over 55,000 people. This is clearly one of the reasons that Twitter is the second-largest source of traffic to my blog.

Tweeteffect.com

Tweeteffect‘s claim to fame is that it analyzes recent tweets and correlates them to the exact time people either join you or abandon you as followers. It’s difficult to see any correlation between tweets and follows or dumps, so this seems of little utility to me. Your mileage may vary.

Topsy.com

Topsy Analytics, part of Topsy’s extensive social media analysis products, gives you “Mentions That Matter. We only show those mentions within Twitter that are significant and valid. Significant to us means a tweet that’s been retweeted or contains a link.” The tool also shows individual tweets with a variety of metrics.

Tweetstats.com

Tweetstats is unlike the other programs here. For one thing, it took almost 5 minutes for the site to process the data from Twitter and draw the beautiful charts it then presented. It’s when you realize these charts are all interactive and can be clicked-through to more detailed displays you realize how much data the program is handling.

Twitalyzer.com

Twitalyzer measures your Twitter performance against all other users and comes up with an “Impact score” and a list of influencers. The most interesting feedback from this site was: “Based on sampled data from Rapleaf, @jfbookman’s network skews female and is composed primarily of 35-44 year olds followed by 45-54 year olds.” I’m not sure how much I believe this, especially when I notice they have my location off by about 220 miles.

Tweetgrader.com

Tweetgrader, a Hubspot tool, also grades your performance on Twitter. In this case it comes up with a numeric score (scope out my perfect rating!) and a keyword cloud based on recent tweets.

Backtweets.com

Backtweets, although it has been purchased by Twitter and may be merged into their other functions, still has a web presence. Backtweets shows yet another scoring system, but also includes lists of your most-shared sites, the people who influence you, and the people you influence.

Owly.com

Owly.com isn’t a Twitter stats site, of course, but the home of Hoot Suite, the useful and free social media dashboard. I use Hoot Suite for a lot of my Twitter things and it includes a link-shortener. When you use these links the program provides a growing suite of analytical tools for examining the effect of your tweets. It tracks clicks, regions, popular posts, top referrers and allows you to create and save your own reports.

There you have it. I don’t think you need to spend a lot of time looking at stats, but a familiarity with analytics is one of the most powerful information tools you can have in your arsenal if you’re going to be marketing your books online.

Find one or two of these tools that give you the information you need to evaluate your Twitter use and you’ll be ahead of the game.