Citigroup Inc is hoping that one of the country's most famous customer service gurus can help it rebuild its reputation -- one Tweet at a time.

Frank Eliason, who gained national media attention for his unorthodox customer service methods at cable television provider Comcast Corp, joined Citigroup in August to direct social media strategy.

In the past five months, he has overseen the launch of a Facebook page, YouTube videos and new blogs for the bank. But most of all, he is helping Citigroup learn to use Twitter, the website that made him famous at Comcast.

Most banks still use Twitter largely for marketing, but Eliason is hoping to use the service more to respond to aggrieved customers, the way he did at Comcast.

Twitter is part of a broader effort by Citigroup to reach out to the younger, wealthy urban Americans that it wants as banking customers -- and to improve the bank's tarnished image. Eliason hopes his methods can help do both.

It's really about building trust and building rapport ... The benefits are not about selling. Hopefully, long-term, you create the right customer experience, you will sell, he said in an interview with Reuters on Monday.

Since the financial crisis, Chief Executive Vikram Pandit has slimmed down the company and abandoned the bank's onetime ambitions to have branches across the United States.

Citigroup has only about 1,000 branches in the United States, compared with several thousand each at rivals Bank of America Corp and JPMorgan Chase & Co.

Instead, Citigroup is using technology to make the most of its relatively small branch network. It is seeking more deposits online and looking at buying a website that allows customers to manage their entire financial lives in one spot.

Citi's going to be an also-ran in terms of branch presence, so it absolutely has to have a digital presence, said Alex Sion, a former Citigroup executive who now runs digital strategy for the marketing consultancy Sapient.

Mark Schwanhausser, senior analyst at financial services consulting firm Javelin Strategy and Research, agreed that using Twitter and other online media is more important for that kind of a bank that is looking for business from highly-connected customers.

Regaining trust is especially important for the bank, which accepted $45 billion in U.S. taxpayer funds during the financial crisis. The government finished selling off its stake less than a month ago, helping Citigroup shed its stigma as a government ward.

The reputation of the banking industry obviously needs to come up and we need to do better than the industry, Eliason said. When you look at all industries, customer service has not always been a priority for these companies. I think that's changing and I hope to lead that change.

BEING DIGITAL

At Comcast, Eliason was the subject of profiles in The New York Times and Bloomberg BusinessWeek, which in 2009 called him the most famous customer service manager in the U.S., possibly in the world.

He famously sent a technician to the home of a customer who complained about his difficulties in setting up cable service. Between 2008 and 2010, his efforts helped Comcast improve its low scores on the American Customer Satisfaction Index, which tracks consumer opinions on more than 225 companies.

Eliason is keeping a lower profile at Citigroup, where he is less likely to personally respond to customer Tweets. But the bank has about 100 employees trained to do so instead.

Citigroup is making other efforts to reach tech-savvy customers. Last month, it opened a high-tech smart bank branch in Manhattan, complete with video phones and free wifi access. Manuel Medina-Mora, head of consumer banking for the Americas, has said Citigroup plans to continue investing in such high-tech bells and whistles to serve clients.

It is not alone in trying to reach customers through social media. Bank of America also has a thriving Twitter account of its own -- @BofA_Help -- which has almost 11,000 followers.

Citigroup's account has about 3,100 followers, so Eliason has a long way to go. But he is trying to set his company apart in the social media sector. Since August, he has quietly turned the @AskCiti Twitter page into an almost 24-7 operation.

The 100 Citigroup employees who are trained to use it will soon respond to complaints with individual Twitter identities, which Eliason said will make Citigroup's online customer service more personal.

And in February and March, the bank will introduce online chat features for customers who use Twitter, so people who have detailed complaints can click to call or even click to chat online with Citigroup employees. They will have to log in to their bank accounts first to ensure that the online chats are secure.

Eliason would not discuss how much Citigroup has invested in building up its social-media efforts.

But few banks are spending much on social media, according to a November report by the financial services consulting firm Aite Group. More than half of the financial companies surveyed said that investments in social media are too small to measure, according to the report. By 2012, about 40 percent of financial companies are expected to spend between 2 percent and 10 percent of their marketing budget on social media.

Citigroup is possibly wasting money, but the amount of money they're wasting, if they are, is so small ... that we can't even measure it, said Aite senior analyst Ron Shevlin.

You have to do some experimentation.

(Editing by Andre Grenon)