The company has not said what it plans to announce at the media briefing at its headquarters in Menlo Park in California.
Last week, it merely invited bloggers and journalists to "come see what we're building".
"There's a lot of speculation. Nothing to me seems to be that certain," said Jefferies & Co analyst Brian Pitz.
"If I were to bet, I'd think it was something that was ad-platform related. I'm not convinced on the phone."
Mr Pitz pointed out that Facebook officials, including CEO Mark Zuckerberg, had previously said making a smartphone would be the "wrong strategy".
Since the company's current search functions are limited, users would most likely welcome a better way to search Facebook.
Yesterday, Facebook's stock opened above $32 (£19.90) for the first time since July as anticipation about its upcoming products and financial results underscored Wall Street's renewed confidence in the social network.
Its shares are up roughly 17% since the start of the year, and some analysts believe the recent gains may have more to do with the company's upcoming fourth-quarter financial results, which are due out on January 30.
"The stock is up because they have driven a dramatic increase in the ad load of their mobile app which is giving investors hope that they exceeded expectations," said BTIG analyst Richard Greenfield.
Facebook, the world's number one social network with one billion users, became the first US company to debut on the stock market with a value of more than $100bn (£62bn).
Its value subsequently plunged by more than 50% amid mounting concerns about slowing revenue growth and the challenges of making money as users shift from personal computers to mobile devices.
Facebook surprised Wall Street in the third quarter by announcing that mobile ads accounted for 14% of its total ad revenue.
Some analysts expect the company to report further growth in its mobile ad business for the fourth quarter.
Mr Zuckerberg, who founded Facebook while studying at Harvard, has said mobile is the "most misunderstood aspect" of Facebook.
But he has repeatedly poured cold water on rumours that Facebook would build its own smartphone to compete against Apple (NasdaqGS: AAPL - news) 's iPhone and others based on Google (NasdaqGS: GOOG - news) 's Android operating system.
However, at a conference in September, he said he believed search could be a ripe area of growth for his company.
More From Sky News