Facebook is set to release an update to its iPhone app on Thursday in response to a deluge of complaints by users who have suffered crashes, failed delivery of messages and other faults.
Tens of thousands of iPhone owners around the world have posted one-star reviews on Apple's App Store – the lowest possible rating – in the three weeks since the prior version of the Facebook app was released.
Facebook for iPhone has been among the most downloaded apps on Apple's smartphone since its launch in 2009, with 84 million active users, or roughly half of all iPhone and iPod touches in use today. Mark Zuckerberg, the social network's founder, said last year that mobile was its top priority for 2011.
More than 20,000 people have posted negative reviews on the U.S. App Store, compared with 4,000 positive reviews. British users have posted more than 7,000 comments about its "diabolical," "rubbish" and "awful" recent performance.
The user revolt comes as Facebook faces growing competition from Google's new social network, Google+, which released its iPhone application to generally favourable reviews this week.
Twitter, another Facebook competitor, is also putting greater emphasis on its mobile efforts. Dick Costolo, Twitter's chief executive, told a conference in Colorado organized by Fortune magazine this week that mobile usage of the short-messaging service was growing by 40 per cent every quarter, saying: "We want Twitter to be the world in your pocket."
One UK iPhone owner said of the Facebook app before its update: "This is a fundamental iPhone app, I use it constantly it's great for that but the latest round of updates have been shocking! It's now riddled with bugs, repeatedly crashes, doesn't update properly… Pick up the slack Facebook!"
Another said: "I'm glad to see the new Google+ app is now on the iPhone… This means we don't need Facebook any more."
Facebook declined to comment other than to say that a new version of the app would be available on Thursday. A number of previous iPhone updates in recent months have failed to stem users' complaints.
A Facebook spokesperson said that it had only one engineer working on its iPhone app full-time. Its wider mobile team has been working on other mobile platforms, including helping handset makers such as HTC and INQ to create customized Facebook phones using Google's Android operating system.
Figures from AppData, which monitors Facebook applications, suggests that the number of people using Facebook for iPhone has continued to grow in the past month, although usage is below its all-time high of 108m per month.
Analysts have been perplexed by Facebook's lack of an application for Apple's iPad. Around 5m people use third-party Facebook apps on the iPad, suggesting ample demand.
"Facebook has never really done aggressive innovation around the [iPhone] app," said Benedict Evans of Enders Analysis in London, since its original release in 2009. "There has always been that sense that it lagged behind the Facebook feature set. It got location, but it doesn't have any games."
Joe Hewitt, the creator of Facebook for iPhone, left the company in May, after earlier stopping work on the project amid reports of his frustration at Apple's developer policies.
"Facebook has had an ambivalent attitude towards iPhone apps," Mr Evans said. "Its ability to put its extended platform onto mobile may conflict with the way Apple tries to control what native apps can do, particularly in terms of payments."
Facebook's Credits system of payments within applications running within its social network – its main source of revenues beyond advertising – would be likely to break Apple's terms and conditions for its iOS platform, Mr Evans added.