Twitter is a popular micro-blogging site.
"We're constantly working to make Twitter search the simplest way to discover what's happening in real time," said Twitter engineer Frost Li in a blog post.
"To that end, today we're introducing search autocomplete and 'People you follow' search results to twitter.com. In addition to recent improvements like related query suggestions, spelling corrections and more relevant search results, these updates make it even easier to immediately get closer to the things you care about."
The "search autocomplete" shows the most likely terms for a query. So a user who types "Jeremy" might get a suggestion for basketball star Jeremy Lin before finishing the full name.
Twitter will also allow users to see tweets about a given topic from only the people they follow if they select that option.
"Viewing tweets about a topic from just the people you follow is a great way to find useful information and join the conversation," Li said.
Twitter, which allows its members to post brief comments, links or pictures, claims to have more than 140 million active users, with the largest number being in the United States.
A recent survey found one in seven Americans who go online use Twitter and eight percent do so every day.