Which Google service will Facebook try to disrupt: Android or Search?

Facebook plans to hold a press event today that—if rumors are factored in—could launch a new search feature, ad platform, improved apps, or even a smartphone that would bring it up to speed with, or at least give it an edge against, its primary foe, Google.

Facebook will kick things off at 10 a.m. PST at its headquarters in California, but the company hasn’t given any hints about what is in store other than inviting the media to “come see what we’re building.”

The Wall Street Journal, via the Associated Press, said a new search function, if unveiled, would likely introduce “a better way to sift through Facebook for people, businesses, events and everything else available on the vast online network.”

Pocket-lint.com said definitively that Facebook would launch its own search engine soon. The website claimed it heard from sources that Facebook plans to take on Google “at its own game.” Although exact details as to how are unclear for now, the website said Facebook’s new search feature would “shake everything up.”

Business Insider, however, asserted a new mobile ad product is in the works. Advertisers can only buy display ads on the desktop version of Facebook at the moment, but a new mobile strategy will soon, according to the website’s unnamed sources, “allow advertisers to buy mobile ad inventory through FBX.”

PCMag tossed rumors to the wayside and called for better mobile apps. It referred to the existing apps as “often sluggish and unstable,” but it also admitted the native apps work better than the HTML5 versions. Still, the website said, Facebook “needs to announce” an overhauled offering.

PCMag might get want it wants, too, as TechCrunch said it recently saw an “employee-only iOS app build of an evolved form of Facebook’s mobile news feed, which ditches the empty blue and white chrome for full-screen photo tiles and overlaid text.” While the report did not claim the new look would release soon, it pointed to Facebook’s event as a likely launch date. However, it also said the mobile app redesign could “get scrapped altogether.”

Speaking of mobile, the big fish in all this talk is a Facebook phone. The idea has surfaced repeatedly in recent years, and it is of course debuting again with today’s mysterious event. The Wall Street Journal cited a quote by Chief Executive Mark Zuckerberg last fall, where he said a phone is “clearly the wrong strategy” for Facebook, as proof that the social network is not building a smartphone. PCMag, too, said a Facebook phone is “still a stupid idea.”

Despite such strong opinions against a Facebook-branded mobile device, speculation grows. Even CNET called today’s secret announcement “a big deal,” as unidentified sources at Facebook have led the website to believe, and said a phone, if unveiled, would likely come from a manufacturing partner like HTC and run a forked version of Android like Amazon’s Kindle Fire line.

Investor and blogger MG Siegler also claimed, while citing multiple sources, that Facebook will announce a phone, but he noted it will probably not include any hardware built by Facebook.

With that said, whatever happens today, one thing is for sure: Facebook will likely try to disrupt one of Google’s services. Whether it is a phone, search, ads, or even more enticing mobile apps, Facebook will use, or at least should use, today’s press event to up the ante and give Google a run for its money.