Jessica's Alba's startup just got more funding and is now worth $1.7 billion. Uber was recently valued at $51 billion -- the largest valuation for a private company in the world. Airbnb is allegedly worth $25 billion.

The list goes on. This rather long list of startups with eye-popping valuations is concerning some investors that there is a massive startup bubble that could pop soon. The 6-year-old bull market has less momentum this year, and other bubbles, such as Chinese stocks, have already burst.

But LinkedIn (LNKD)'s cofounder Reid Hoffman sees no reason for the growing "skepticism about these billion-dollar maybes."

He says the growth of cheap technology makes it possible for startups to grow in size pretty quickly today.

"A couple college students can build an application that 100 million users might adopt in a matter of months," he points out.

In this environment, investors are correctly valuing the companies at "a billion dollars or more," Hoffman says.

Related: Jessica Alba's company now worth $1.7 billion

Hoffman cited research from venture capitalist Aileen Lee of Cowboy Ventures that showed only a small number of American tech startups -- 39 out of 60,000 -- had valuations higher than $1 billion between 2003 and 2013.

Those 39 companies were members of what Lee called the "unicorn club." Facebook (FB) was in the unicorn club when it was a private company. As was LinkedIn, valued at $4.25 billion. Now its market cap is $24 billion.

Now there are many more unicorns: over 125 tech startups are worth $1 billion or more, according to CB Insights, a venture capital database.

Hoffman says it's OK that the unicorn club is bigger. The world is more digitally connected today than in 2003 with smartphones, tablets and computers. This new "Networked Age" as Hoffman says creates more opportunity for new companies.

It's because of all of these reasons Hoffman says he wouldn't place too high of a premium on "investors who believe...we're in the midst of a bubble."