New Delhi: With a broader vision to grow aggressively worldwide in key markets, Twitter spent a hefty sum in 2013 on buying technologies and talent. A recently filed S-1 shows that while the company spent $52.2 million in cash and stock on acquisitions in 2012, it doubled the amount to $112.5 million in the first half of 2013. Strikingly, the figure does not include the company's largest acquisition to date, MoPub, which was purchased in September for $305 million in stock.A rough estimate shows that the company has spent over $417.5 million on acquisitions this year (and it is still counting). This means that the company's acquisition spree has grown nearly 700 per cent over the past one year. Twitter's programmatic buying denotes the company's expansion into mobile, analytics and second-screen viewing, to further its goals. The move also positions Twitter as a more comprehensive platform for publishers and advertisers to engage in real-time conversations.Twitter's largest acquisition till date is the $305 million purchase of MoPub. Detailing about this purchase, Adam Bain, head of revenue at Twitter, said, “The company plans to "use MoPub's technology to build real-time bidding into the Twitter ads platform so our advertisers can more easily automate and scale their buys."Recently the company came out with its IPO and its lack of profits proved to be no obstacle in raising as much as $2.1-billion in its IPO. Its current share price of around $41 gives it a market value north of $22-billion.Reports suggest that post its initial public offering, the company is all set to embark on an acquisition spree, going on the hunt for companies to help bolster its monetisation efforts.Below are some quick facts on Twitter's acquisitions so far this year.Startup: CrashlyticsSale price: Reportedly $100 million in cash and stockAcquisition date: January 2013What it is: A startup that helps developers track down and fix bugs in their apps. Startup: Bluefin LabsSale price: Estimated $50 million to $100 millionBuying date: February 2013What it is: A data analytics company that tracks social-media reaction to TV programs and provides that data to TV networks and advertisers. Startup: We Are HuntedSale price: UndisclosedBuying date: April 2013What it is: A streaming music service with recommendation features. Startup: UbaloSale price: UndisclosedBuying date: May 2013What it is: Computing technology outfit working to increase efficiency in large computing environments. Startup: Lucky SortSale price: UndisclosedBuying date: May 2013What it is: A company tackling how to make large data sets easier to analyze, summarize and visualize. Startup: SpindleSale price: UndisclosedBuying date: June 2013What it is: A tool that uses geolocation and data from social networks to provide users with suggestions for things to do in their local area. Startup: MarakanaSale price: UndisclosedBuying date: August 2013What it is: A developer of open-source training for software engineers. Startup: TrendrrSale price: UndisclosedBuying date: August 2013What it is: A social analytics company that tracks conversations around TV viewership and provides associated insights to media companies. Startup: MoPubSale price: Reportedly $350 million in stockBuying date: September 2013What it is: A mobile-focused digital ad exchange that allows ad buyers and sellers to make automated transactions in real time.