Twitter faces lingering doubts about its future

The number of people who log into Twitter at least once a month rose less than 3 percent from the previous quarter.

Shares plunged to a record low of $28.69 in the middle of the trading hours. At the end of day, shares had fallen 5.6 percent to $29.30 -- the lowest since May of last year.

"The bottom line for Twitter is that after nine years of its existence, my mother still doesn't understand what it means to 'hashtag' something," wrote Ben Schachter, an analyst at Macquarie Capital, in a note to investors. "But she does understand what it means to 'like' something," he added, referring to Facebook's ubiquitous feature.