According to the latest data from Hitwise about Twitter users in the UK, Twitter has become an important source of traffic for entertainment sites, other social networks, and news and media sites, but compared to other social networks, Twitter only sends a small amount of traffic to online retailers. Hitwise’s Robin Goad also points out that Twitter is now the 30th biggest source of traffic in the UK and accounts for 1 out of every 350 visits to a typical web site in the UK.

According to this data, just over half of Twitter’s traffic (55.9%) goes to “content-driven” sites like blogs, news, other social networks, and entertainment sites. In contrast only about 9.5% of all of Twitter’s visitors go to “transactional web sites” in the travel, business, finance, and online retail categories. For Facebook, this number is 14.7% in the UK, and for Google searches it’s over 30%.

At first glance, these numbers for Twitter look a bit low, but after looking at how people use Twitter, these numbers do make a lot of sense. According to anotherrecent study from the Conference Board, the top reasons for people to tweet are “connect with friends (42%), update their status (29%) and look for news (26%).” The study also found that two out of three Twitter users use the service to interact with friends.

It is also interesting to note that another recent study from the NPD Group found that Twitter users are more likely to buy music than non-Twitter users. Chances are that this is also related to the demographic makeup of Twitters user base which tends to skew a bit older, but it also clearly shows why Twitter could be such a valuable source of traffic for retail sites.

In many ways, it is probably a good thing that brands are still trying to figure out how to best utilize Twitter. If brands want to make good use of Twitter – which, for many would mean driving traffic to their sites – they have to become part of the community. We would love for Twitter to find a viable business model so that the service can stay afloat even as it grows, but in the end, most of us use it as a personal communications medium and unless brands can find a way to become part of that in an authentic, non-creepy way, they won’t be able to profit from Twitter’s rapid growth – and maybe that’s a good thing, too.