Which auto insurer is flying highest on Twitter?

State Farm Insurance may be the country’s largest auto insurance company, but it’s not the most popular carrier when it comes to the micro-blogging service Twitter.

Allstate, the country’s second largest auto insurer, has the most Twitter followers among auto insurers — 17,847 — as of May 17, 2011. Allstate is followed by USAA (15,051), State Farm (11,801) and Progressive (7,357).

“Everyone watches the numbers, how many followers we have, but what I care about are trends: Are people engaged with our content and do they find value?” says Roger Tye, Allstate’s director of consumer engagement.

Recurring themes in the tweets of auto insurance companies: new products, insurance tips, and comments from satisfied or dissatisfied insurance consumers.

For instance, a May 4 tweet from Esurance points followers to a new blog: “Do you get the highway heebie-jeebies? Our new blog discusses top driving phobias and how to overcome them.”

And on May 5, Allstate retweeted this message from Twitter user Brandy Hagelstein: “To follow up: @Allstate is on the ball. What good is a complaint if you can’t follow it w/praise when they do good. Thanks @Allstate.”

“Our guiding principle is: What does the customer expect and how can we be responsive?” Allstate’s Tye says.

State Farm has the busiest Twitter feed, with 6,156 tweets as of May 17, 2011. That’s the total number of tweets State Farm has posted since the company started using Twitter. State Farm is followed by Allstate (4,099) and American Family Insurance (3,718).

Susan Rouser, Progressive’s digital content manager, says Twitter offers “a great opportunity to have a conversation with our community, from thanking them for the positive things they say about us to addressing concerns and complaints.”

Here are the “handles” for the top 10 auto insurance companies on Twitter:

Allstate
@Allstate

USAA
@usaa

State Farm
@StateFarm

Progressive
@Progressive

Nationwide
@Nationwide

Travelers
@TRV_Insurance

GEICO
@GEICO

Liberty Mutual
@libertymutual

American Family
@amfam

Esurance
@esurance

–Kevin Lyons