Marketo gets scooped up into the private world for $1.79 billion

Marketo shareholders will receive $35.25 in cash per share -- a sum the company says represents a 64 percent premium over its closing price earlier this month, before reports emerged that it was exploring strategic alternatives.

The deal is expected to close in the third quarter of 2016. Marketo's headquarters will remain in San Mateo, California, the company said.

"The acquisition will allow Marketo to continue to focus on customer success and to remain the independent category leader," said Phil Fernandez, Marketo's chairman and CEO.

Marketo's marketing-automation software is designed to help companies develop long-term relationships with their customers. Shares of the company's stock were up more than 9 percent on Tuesday.

Some Marketo customers are worried by the acquisition, according to Ray Wang, founder and principal analyst with Constellation Research.

"In the past, when Vista has made acquisitions like this, such as of Tibco, they've done weird things," Wang explained.

Asking employees to take "weird management tests" is one example, Wang said. "That's part of the process."

So, in addition to the talent loss that Marketo would have naturally experienced following its 2013 initial public offering (IPO), there will likely be "a little bit of an exodus" following this latest news, he predicted.

Private equity firms like Vista also "typically stretch out R&D investment," Wang said, pushing out deadlines on projects already under way. They often tend to reduce expenditures on sales and marketing as well, as a way of cutting costs.

"Pretty soon it's just about keeping a maintenance stream of customers and not really growing the market," he explained. "What most of our customers are worried about is the lack of innovation that could occur, especially given Vista's reputation."

That's not to say that there aren't potential upsides to the deal, however. Vista has already made numerous other acquisitions of related technologies, so "they could make some synergies here," said Cindy Zhou, a vice president and principal analyst with Constellation Research.

Vista Equity Partners couldn't immediately be reached for comment.