LAS VEGAS - With 55 days until the election, President Obama invoked his deep roots in political organizing, for the first time joining his campaign's monthly video conference call to rally thousands of his grassroots volunteers and offer tips for success. ?

? "I hope everybody is as determined as I am, as energized as I am," Obama said Wednesday night from a computer web camera backstage at his Las Vegas rally. The appearance was broadcast online nationwide.

"You guys are heart and soul of this campaign and you've been for a very long time. Dating back to 2007, 2008 some of you've been involved for years now in the campaign … every step of way you've been there and my main message today first and foremost is just to say thank you,"? he said.

Campaign sources say they had expected between 2,000 and 4,000 volunteers to dial into the video conference from around the country, but ended up with 6,000 . Most of them were "team leaders" in the Obama organization, tasked with organizing volunteers and building the organization, an official said.?

? They received from the Grassroots Organizer-in-Chief a primer in how to get votes.?

?"Here's the deal," Obama said. "2008 was so special that in some ways people naturally registered, naturally turned out. This time we're coming off of three and half years of really difficult economic times. There are folks some places that feel discouraged. And its not as trendy maybe to participate as it was in 2008. So even though we've really done a great job hitting our voter registration numbers, we've got to push. … Keep in mind the other side have millionaires and billionaires who are writing $10 million checks and running non-stop ads. We're being outspent 3-1, 5-1 in some of these places. The good news is money like that is not going to beat great people on the ground who know their neighbors, know their friends and believe in what they're doing. But they can beat us if we are not on the case."?

?On developing leaders inside his own campaign, Obama said there was one simple rule to follow: "Listen more than you talk."?

?"If all you're doing is just telling them you got to vote for Obama because x-y-z but you're not asking people what are they going through, and what struggles and challenges are they experiencing, they're not going to be as engaged," he counseled. "People step up to meet these challenges particularly if they have got the support of other people who are interested in the same mission."?

?On voter registration, Obama seemed to take a swipe at the voter ID laws now being challenged in various states. "Our job is to try to make it as easy as possible for people to exercise that franchise, that's what we are all about," Obama said. "Just from a practical point of view…there are a bunch of states where if turnout is like it was in 2010, we lose, if turn out is like it was in 2008, we win. And so its pretty straight forward. If you're in… all the battleground states basically, the difference between us winning or losing that state and then the difference between us winning and losing the elections as a whole may come down to a few thousand votes. So that person you register could end up being a deciding factor," he said, almost with a dire tone.?

?Obama signed off with his campaign slogan: "Good job. Keep it up. Forward."?

?? Obama first joined a volunteer teleconference on his birthday in 2011. The campaign has been holding them monthly with volunteers around the country since Obama For America has been operating. Other big names to join the line include first lady Michelle Obama and Vice President Joe Biden.

ABC News' Devin Dwyer contributed to this report.