Twitter (NYSE:TWTR) and Pinterest (NYSE:PINS) occupy two well-defined niches in the crowded social media market. Twitter is a top platform for following politicians, journalists, celebrities, and companies. Pinterest encourages users to share their interests via virtual pinboards.Both stocks recently spiked after their latest quarterly earnings impressed investors. But is either stock still worth chasing? Let’s dig deeper to see which stock is the better social media play for 2020.Twitter generated 88% of its revenues from ads — in the form of promoted tweets, accounts, trends, and app-install ads — last quarter. The rest mainly came from its data licensing business, which sells a “firehose” of tweets to analytics firms, media companies, and other clients.Pinterest generated all of its revenue from ads last quarter. These ads include promoted pins, multi-pin carousels, shoppable pins, app-install pins, and story pins — which allow merchants to add up to 20 pages of pins, text, and links. Retailers can also upload their entire catalogs to Pinterest as shoppable pins.Twitter measures its growth in mDAU (monetizable daily active users), a proprietary metric which excludes fake, bot, and spam accounts. Its total mDAUs rose 21% annually to 152 million last quarter. Its international mDAUs grew 22% to 121 million, led by Japan, while its US mDAUs rose 15% to 31 million.Pinterest measures its growth in MAUs (monthly active users) without any adjustments. Its total MAUs rose 26% annually to 335 million last quarter. Its international MAUs grew 35% annually to 247 million, while its US MAUs rose 8% to 88 million.Twitter and Pinterest both generate stronger user growth overseas, but their larger overseas audiences generate far less revenue than its American users. Twitter still generated 59% of its revenues in the US last quarter, while Pinterest relied on its home market for a whopping 88% of its revenues. Both companies believe that they can gradually boost their monetization of overseas users.Pinterest is generating much stronger revenue growth than Twitter, but its growth decelerated over the past two quarters.YOY = Year-over-year. Source: Company quarterly reports.Twitter expects its first quarter revenue to rise 5%-12% annually during the first quarter of 2020. Analysts expect its full-year revenue to rise 15% to $4 billion. Pinterest didn’t offer a first quarter forecast, but analysts anticipate 38% revenue growth. It expects its full year revenue to rise 33% to $1.52 billion.Twitter remains profitable by both GAAP and non-GAAP metrics. On a reported basis, its net income grew 22% to $1.47 billion in 2019. Its adjusted EBITDA, a non-GAAP metric which excludes stock-based compensation and other one-time charges, rose 1% to $1.21 billion.Those growth rates look healthy, but Wall Street expects Twitter’s non-GAAP earnings to slide 62% to $0.91 per share this year, due to bigger investments and a planned headcount increase of 20% to focus on new engineering, product design, and research initiatives.Pinterest is unprofitable on a GAAP basis. Its net loss widened from $63 million in 2018 to $1.36 billion in 2019, but that was mainly caused by its post-IPO expansion last year. Its adjusted EBITDA, which cuts through that noise, improved from a loss of $39 million to a profit of $17 million.Pinterest expects its adjusted EBITDA margin to be “flat to up slightly” in 2020, but didn’t provide an exact forecast. Analysts expect it to achieve non-GAAP profitability this year with a slim profit of $0.08 per share.Pinterest trades at a lofty 92 times forward earnings, compared to Twitter’s forward P/E of 34.However, Pinterest’s stronger user and revenue growth — along with its straightforward business model of monetizing pins and converting them into mini-storefronts — arguably justify that premium valuation. Twitter, which constantly deals with toxic tweets and trends, could struggle to evolve its platform and expand its ecosystem.Therefore, I believe that Pinterest has more room to run than Twitter this year. It still has plenty of room to grow by monetizing its overseas users, its pins could appeal to retailers chasing the “social shopping” trend, and its growth indicates that it can still hold its own against Facebook’s Instagram.