Up until April, the hit mobile doodling game Draw Something, which first debuted in February, was growing at an unprecedented rate — amassing 20 million daily active users at one point. In late March, the game's parent company, OMGPOP, was snatched up by online gaming giant Zynga for an eyebrow-raising $200 million, and usership has declined since. In April, the title lost a third of its then-15 million daily active users, with 900,000 people abandoning their artistic ambitions in the last week of April alone. What's behind Draw Something's sudden free fall? Here, three likely theories:

1. The Zynga effect
The "Zyngafication" of Draw Something may have "soured many players' relationship with the game," says Bobbie Johnson at GigaOm. Having Facebook and Twitter integration pushed into your face is one thing, but not-so-subtle advertisements from companies like Doritos and the NHL have awkwardly injected a number of "brand-related words into the game's dictionary," turning players off. Unfortunately, Zynga has few other revenue-generating options, says Paul Tassi at Forbes. With Draw Something, unlike games like Farmville or Mafia Wars, "there really aren't a lot of fake items that can be sold within the game for real world cash." You can't blame players for not wanting to open their pocketbooks for something like a new color palette. So they're stuck with annoying ads.

2. Egregious game glitches
Accumulating that many users in such a short period of time can create problems for any company, says GigaOm's Johnson. Draw Something users faced an obvious "scaling problem, with servers struggling to meet the demand of more and more downloads." For many players that meant the frustration of suddenly dropped games or lost moves — bad news for a title designed for instant gratification. New owner Zynga's massive servers should have helped rectify the bugs, but nothing really changed and gamers jumped ship.

3. Draw Something is too easy
Games like Angry Birds and Farmville get "progressively more challenging" the more you play, which makes them truly addicting says JD Rucker at TechiDraw Something, with its repetitive sketching of the same words, "gets annoying, even boring" with ongoing use, and has all the ingredients of a passing fad. In retrospect, it's like Zynga sunk "huge amounts of stock in Pogs or Members Only jackets," says Forbes' Tassie. Now the company is learning its lesson the hard way.