The number of words in the average US search query is on the rise, with longer search queries – averaging five or more words in length – increasing 10% overall in January 2009 vs. January 2008, according to data from Hitwise (via MarketingCharts).

The most notable change was in search queries that were eight or more words. These were up 22%. Over the same time period, shorter search queries, averaging 1 to 4 words in length, have decreased 2%, Hitwise said.

Though Hitwise does not offer any explanation for the increasing length of search strings, the phenomenon could potentially be because internet searchers are growing more sophisticated in their searching habits, or might be attributable to the fact that longer searches may now be necessary to find more specific information amid growing web clutter.

Chris Brown, the pop singer recently accused of abusing singer Rihanna, was the most searched-for personality by US Internet users for the week ending February 14, 2009. Unsurprisingly, Rihanna followed Chris Brown as the second most searched-for personality. Joaquin Phoenix’s bizarre appearance on David Letterman earned the #5 spot among the Top 20 as searchers looked online for video clips of the interview.

While US Internet users are clearly fascinated by celebrities and scandal, they also remain interested in local news and history. Nadya Suleman, the woman who gave birth to octuplets, was the fourth most searched-for personality outranking major celebrities, including Grammy winner Lil Wayne (#11), Oscar presenter Miley Cyrus (#17) and Oscar Best Actress nominee Angelina Jolie. Abraham’s Lincoln 200th birthday and Charles Darwin’s 200th anniversary being this year also drew many US Internet users to search about them, ranking as the 7th and 8th most searched-for personalities, respectively.

Twenty most searched for personalities in the US, week ending 02/14/09
1 chris brown
2 rihanna
3 jeremy lusk
4 nadya suleman
5 joaquin phoenix
6 robert pattinson
7 charles darwin
8 abraham lincoln
9 eliza dushku
10 rush Limbaugh
11 lil wayne
12 salma hayek
13 carrie underwood
14 harriet tubman
15 hulk hogan
16 oprah
17 miley cyrus
18 jennifer aniston
19 angelina jolie
20 rachel ray