March 11 (Reuters) - Shares of Roblox Corp jumped on Thursday, building on the gaming platform’s almost 55% rise on its stock market debut a day earlier as well-known exchange-traded fund operator Cathie Wood bought into the company. The California-based company’s stock was up 12% in premarket trade, after rising more than 20% earlier in the day. Wood’s ARK Next Generation Internet exchange-traded fund (ETF) said it had bought more than 500,000 shares of Roblox, weighting it at 0.47% of the fund. Wood, a long-time Tesla bull, has a massive online following and is a popular topic of discussion on the Reddit forums that are seen as having driven this year’s growth in influence for a social-media savvy herd of small-time traders. ARK Invest on Wednesday also sold a little over 67,000 Facebook shares from the ARKW ETF, amounting to about 0.3% of the ETF’s assets. Message volumes on Roblox on trading-focused social media site Stocktwits soared more than nine-fold on Thursday, with more than 80% of users’ messages reflecting positive sentiment toward the scrip, data showed. Usage and spending on Roblox has surged as kids stuck at home in the COVID-19 pandemic spent more time on the platform, fuelling an 85% year-on-year jump in daily active users in 2020 and a surge in monthly in-app sales. An average 37.1 million people globally log on to Roblox daily to connect with friends and play popular games like “Jailbreak” and “Speed Run 4”.