Facebook (FB) shares pared their initial post-earnings gains Thursday after its blowout quarterly report last night. The company beat expectations across many metrics, but also warned that future ad revenue could be impacted by moderating "ad load," a measure of the number of ads shown to any given user. Despite the commentary, Wall Street analysts remain largely upbeat on the stock, with research firm Monness Crespi a bearish outlier this morning.

FACEBOOK Q2, MODERATING AD LOAD: Wednesday evening, Facebook reported Q2 earnings per share of 97c on revenue of $6.44B, handily beating estimates of 82c on $6.02B. Mobile advertising revenue comprised 84% of ad sales, and monthly active users grew 15% year over year to 1.71B while daily active users grew 17%. Speaking during the subsequent conference call, Facebook CEO Mark Zuckerberg said time spent per person increased double-digit percentages year over year across Facebook, Instagram and Messenger. Facebook CFO Dave Wehner, however, cautioned that comparisons will get tougher in the second half of the year and warned that the company now has a limited ability to continue increasing ad load before detracting from the user experience, adding that "since ad load has been one of the important factors in our recent strong period of revenue growth, we expect the rate at which we are able to grow revenue will be impacted accordingly." Separately, Zuckerberg hinted that searches on Facebook could be nearing monetization.

SNAPCHAT THREAT: Despite Facebook's quarterly beat, Jefferies analyst Brian Pitz questions whether the rise of Snapchat will impact Instagram growth. His analysis suggests Snapchat could hit 3%-9% of Facebook's 2018 earnings per share, with the beginnings of that impact starting to be felt as soon as this year's fourth quarter. Looking for early evidence of the potential shift, Pitz notes that Q2 engagement actually ticked down in the U.S. and Europe, the first decline in about four years, though he concedes the counterpoint that overall time spent per person grew double-digits across Facebook's platforms. Pitz also highlights the now "more challenging" 2017 given tougher comparables and management commentary around ad loads. The analyst keeps a Buy rating while upping his price target to $170 from $160 on the solid Q2 report.

MONNESS SAYS TAKE PROFITS: While still recognizing the strong quarter, Monness Crespi analyst James Cakmak downgraded Facebook to Neutral. It is unclear, he argues, whether growth in expensive mobile ads is sufficient to offset moderating ad load, and ad pricing could also be pressured. Additionally, Facebook's increasing focus on video is likely to necessitate increased spending to build out infrastructure. Cakmak is "quite optimistic" on emerging opportunities in Messenger, Oculus, and search, but meaningful monetization of those efforts "may take longer than expected," leading him to recommend taking some profits here.

GENE MUNSTER STILL POSITIVE: Piper Jaffray analyst Gene Munster reiterated his Overweight rating and raised his price target to $185 from $170 after Facebook's report. The thesis "remains intact," he says, with Facebook core still benefiting from growing ad load and Instagram now contributing meaningfully, while optionality in WhatsApp and Oculus is largely untapped. Taking the wider view, the analyst sees Facebook "in the lead position as it comes to the future of connectedness," and he expects continued strength in near-term results even as the company works toward its long-term vision.

SOLUTIONS TO SLOWING AD LOAD: Baird analyst Colin Sebastian reiterated an Outperform rating on Facebook and raised his target to $155 from $135, saying the strong quarter confirms "continuing momentum" in both advertising and usage. The company continues to capture a "significant portion" of the shift towards mobile advertising, and while easy gains in ad load appear to be abating, "several growth levers" can still be pulled, including price increases from richer ad products and better targeting, Sebastian said.

PRICE ACTION: Shares of Facebook, which initially jumped more than 7% in late trading Wednesday, have pared their gains and are up about 1.5% to $125.26.