Source: Twitter

As the saying goes, "Good artists copy; great artists steal." Twitter (NYSE:TWTR) investors can certainly relate at the moment.

Twitter's shares are markedly out of favor. The pressure is on for product-focused CEO Jack Dorsey to create one or more new products that will both complement Twitter's core business, while also addressing its user-growth problems.

Interestingly, word broke last week that the Chinese equivalent of Twitter -- Sina's (NASDAQ:SINA) Weibo service -- plans to copy Twitter's reported product strategy in a move that could offer Twitter investors some real-world insight into the viability of its own product strategy.

Weibo gets wordy
According to a note sent to developers last week, Sina's Weibo plans to begin testing an extended version of its microblogging service as soon as Jan. 28, increasing the post limit from 140 characters to 2,000. (Rumor has it Twitter is looking at a 10,000-character limit.) If beta-test feedback proves positive, Sina's Weibo then plans to release the new extended-character format of the service to its 200-million-strong user base one month later.

Much like Twitter, it appears Weibo is acutely aware of the tightrope walk of a balancing act it needs to navigate. On one hand, spurring future growth requires adding some kind of new product -- in this case, a new long-form content type into its microblogging platform. However, in doing so, Sina's Weibo must also not disenfranchise its core user base.

According to reports, Sina's Weibo plans to limit the new-character cap at closer to 2,000 Chinese characters versus the 10,000 characters that Twitter is reportedly considering. Either way, the reaction to the Weibo's product shift will certainly provide Twitter investors with some kind of useful insight as to the odds of success of its potenitally forthcoming product expansion, and that alone is valuable.

The case for 10,000 characters
The key to understanding why Twitter is considering such a dramatic shift in its product strategy is to understand the core problem facing the company -- user growth. See for yourself.

Source: Twitter investor relations.

During the past 10 quarters, Twitter has averaged a meager 4.6% year-over-year expansion of its core users. Such slow growth might prove acceptable for a larger social media platform like Facebook, whose 1.6 billion monthly active users (MAUs) total roughly half of all global Internet users. It's also worth nothing that, despite its size, Facebook grew its massive MAU base by 14% year over year during the third quarter.

Plainly said, microblogging alone isn't an appealing enough value proposition to a wide enough audience. As such, the company badly needs to add new features that will appeal to a wider audience, which is where the 10,000 character "blogging" platform comes in.

A buying opportunity?
With its shares cut in half, and a path to renewed growth in the works, Twitter's contrarian buy thesis is becoming more intriguing. Though not cheap in a Warren Buffett, value-investing sense, there's a legitimate case to be made that Twitter's relatively compressed trading multiples actually offer ample upside for investors who believe in its turnaround story.

Twitter is widely expected to switch to full-time profitability in its current fiscal year. All 41 Wall Street analysts who cover the company expect it. Taking the average of those 41 estimates ($0.56 FY 2016 EPS), Twitter stock currently trades at 32 times its forward earnings. That might seem like a lot, and I admit, again, it isn't textbook cheap. However, if any of Twitter's new-user initiatives actually succeed, the effect they could have on Twitter's financial performance could have huge implications for its bottom-line growth.

I think investors should start paying more attention to the down-but-not-out microblogging service. Weibo's upcoming product experiment is the perfect litmus test for investors to gauge whether Twitter's product innovations might resonate with users.