Social media has helped topple governments and has reshaped how humans use technology to interact with their fellow species. But does it make for a good investment?

LinkedIn Corp.'s initial public offering in May was a smash hit after it zoomed 109%, to $94.25, at the close of its first trading day. Since then, it has gyrated between $60 and $122, and traded under $75 as of noon Monday. Meanwhile, non-public social media darlings such as Facebook, Twitter, Groupon and Zynga have generated tons of hype regarding their private valuations and much speculation about if and when they'll go public.

Into this frenzy steps Global X Funds, the New York-based company that this summer filed its registration statement with the Securities and Exchange Commission for the Global X Social Media Index exchange-traded fund, making it the first firm to file a fund in this nascent industry.

How nascent, at least in a publicly-traded sense? The fund will track the Solactive Social Media Index, a listing created by Structured Solutions AG in Germany that's still under construction. Global X says the index should be finalized by the time the fund is ready to go live. Structured Solutions' social networks index, which is unrelated to the Global X fund, has just 10 companies, including LinkedIn. In short, this space has virtually no track record.

According to Global X's filing, the social media index will screen for liquidity and be weighted according to a modified free-float market capitalization. The social media fund will be passively managed and will invest at least 80% of its assets in the securities of its underlying index. There was no mention of the fund's fees and expenses.

The ETF will trade on the NYSE Arca exchange under the ticker symbol SOCL. Global X plans to start marketing the fund this autumn.

The social media fund will join the ever-growing trend of ever-narrower niche investments among ETFs. Recent examples in the technology sphere include the First Trust NASDAQ CEA Smartphone Index Fund (FONE) and the First Trust ISE Cloud Computing Index Fund (SKYY).

Global X's social media fund joins its existing roster of niche ETFs that includes the fishing industry (FISN), fertilizers and potash (SOIL) and food (EATX).

--Jeff Schlegel