Twitter is testing new search functionality and page layouts aimed at boosting productivity and usability for its rapidly growing user base.

Co-founder Biz Stone explained in a blog post that, after experimenting with the search box at the top of the page, the firm has decided to embed it in the sidebar down the right hand side. The relevant tweets then appear on the homepage.

"This way of experiencing search is aligned with Twitter's simple approach," he wrote. "By default, the tweets you see on your home page are from sources of information that you have curated over time - in other words, the accounts you chose to follow. When you search, you're asking for any tweets that contain the word or phrase you're interested in right now."

Other new features coming "to everyone as soon as possible" include the ability to save a popular search word or term, which will then appear in the sidebar for easy access.

Trending Topics, meanwhile, will offer words or terms related to subjects being referenced most frequently on Twitter at any particular time. A selection will appear in the sidebar for users to click on and investigate tweets related to those subjects.

The new services have not been without their teething troubles, however. Although currently on offer in beta to only "a small subset of Twitter users", the functions appeared not to work when vnunet.com tried to use them.

At the time of writing, vnunet.com was still waiting to hear back from Twitter about the problems.

In related news, Twitter is recruiting for a range of new roles at the company, hinting at its future plans. According to its web site, the firm is looking for an operations engineer, product manager and software engineer for search, as well as a business intelligence software engineer and a user interface designer.