Source: LivePerson.

There's still growth to be had at LivePerson (LPSN 1.95%), but the challenge remains to see if it can milk top-line gains all the way down the income statement. The proactive chat support specialist posted mixed quarterly results after the market close on Monday. 

Revenue climbed 25%, or 28% on a constant currency basis, to hit $59.8 million. It keeps an impressive streak alive. LivePerson has now rattled off 51 consecutive quarters of sequential top-line growth. You have to go all the way back to the sudsy dot-com bubble-bursting days of 2001 -- when revenue went from $1.9 million to $1.7 million between the second and third quarters according to S&P Capital IQ data -- to find the last time LivePerson rang up less in revenue than it did during the three previous months. String together 51 straight quarters of sequential gains and you go from $1.7 million to $59.8 million.

It's not just LivePerson's business that's come a long way. The stock has been a 30-bagger since the day it chimed in with that $1.7 million quarter. 

LivePerson continues to sign up customers to its "intelligent engagement" offering, where companies can use its cloud-based platform for chat, voice, and content delivery support. Its service can be proactive, stepping up when it senses that a virtual shopping cart is about get ditched or someone is getting frustrated surfing through a site's help files. 

It works, but that's to be expected when you're a quarter away from serving up 13 consecutive years of sequential quarterly growth. 

Profitability has been LivePerson's biggest challenge, and it once again closed out the period in the red. It has now posted nine straight quarters of losses, taking some of the air out of the longer streak of sequential revenue upticks. On an adjusted basis -- stripping away stock-based compensation overhead and the amortization of purchased intangibles -- LivePerson's profit of $0.04 a share met analyst expectations. 

The seemingly impressive revenue growth is where LivePerson fell below its own forecast. Just three months ago, LivePerson was targeting $60 million to $61 million in revenue. Making matters worse, it was also eyeing $263 million to $269 million in revenue for all of 2015 back in February. It hosed those goals down to a range between $243 million and $247 million on Monday afternoon. It's also shaving its adjusted earnings outlook by roughly in half.

So, no, this isn't a streak worth celebrating for LivePerson. The stock got rocked in after-hours trading in response to missing its top-line guidance and slashing its outlook for 2015. There's also one more dagger in the dot-com survivor's report: LivePerson's streak of 51 quarters would come to an end during the current quarter even if it lands at the high end of its top-line range. That would then leave us with just the likelihood of 10 straight quarterly deficits as the longest streak at LivePerson.