TheStreet's Action Alerts PLUS Portfolio Manager Jim Cramer is keeping an eye on Facebook's (FB) - Get Report fourth quarter earnings, released after the markets close on Wednesday.

Wall Street expects the Menlo Park, Calif.-based social media giant to post net income of $0.68 a share on sales of roughly $5.4 billion. During the same quarter a year ago, Facebook reported profit of $0.54 per share with revenue of about $3.9 billion.

Facebook is a holding of Cramer's charitable trust, Action Alerts PLUS.

"Facebook users continue to grow," Cramer said. "Even when these companies beat their numbers there tends to be a dramatic fall in the stock, particularly in Facebook.

"The time to buy Facebook is after you've digested the call, listened to them and realized that the stock has completely gotten hammered. Then look at it on 2017 numbers, not 2016 numbers, where it's actually not that expensive."

Facebook saw an average of 1 billion daily active users as of Sept. 30 of last year, representing a 17% increase from the prior year.

Shares of Facebook are down 11.1% since their most recent high on Nov. 11 of last year. The stock has fallen 5.2% since the start of the year, while the broad S&P 500 index slumped over 7%.

Cramer said Instagram is driving things (at Facebook). He said virtual reality is going to be driving things in 2017 and WhatsApp in 2018.

"They have a plan to make it so that they are the worldwide company that you communicate on," Cramer said. "Don't forget, their costs are so low because you provide the content."

Some investors worry about Facebook's user growth going forward. "Compare (Facebook's growth) to Twitter (TWTR) - Get Report , where there's no growth," he said. "Look at the two stocks -- they are a tale of two cities."

Twitter shares, which are also held by Action Alerts PLUS, have lost over 25% of their value since the start of the year.