He's not going to win, and here's why.
Being able to collect money on the internet means nothing in today's political climate. Why?
Because having lots of supporters spread thin over a wide area means absolutely nothing, and that's what internet support is. Go to any small town in America. How many Bernie Sanders supporters are there? One? Two? A half dozen at the most? Even in a decent-sized city, you're looking at maybe a few hundred.
Candidates don't win by sheer number of votes they get across the entire country. Candidates win with regions. They win with having large and numerous concentrations of voters. Ron Paul failed to even come close to winning the GOP nomination in 2012, yet he raised a lot of money in the beginning (I also recall it was more than any other candidate). He failed because his supporters were split and sectioned off into pieces so small, not a single one could overcome the rest of the voters in that region.
Another example, I live in Michigan. In the US Senate, which is a state-wide election, both of our Senators are Democrats. In the House, we have 4 Democrats and 10 Republicans. If you go by the entire state, the Democratic voters in Detroit, Lansing, and Grand Rapids--densely populated areas--overpower the Republican voters in smaller cities and rural areas. Yet, when you split the state up region-by-region, the large population centers no longer skew the numbers in rural areas, and you have the majority of the House Reps as Republicans. This is how the system works.
In order to win the presidency, a candidate doesn't need votes as much as they need states. Sanders' supporters are spread out too thin to be concentrated enough in enough regions to carry those regions. And that's why he doesn't stand a chance.